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Cutaneous apocrine carcinoma is a rare skin cancer arising from apocrine sweat glands. Disease-specific treatments are required for cutaneous adnexal carcinomas due to their heterogeneous treatment responsiveness. This review reports on the epidemiology, diagnosis, pathological features, surgical management, and use of systemic therapies for cutaneous apocrine carcinoma. Diagnosing cutaneous apocrine carcinoma requires presenting with distinctive pathological features and excluding metastatic adenocarcinomas, particularly breast cancer. Clinical findings are essential to exclude metastatic adenocarcinomas, and immunohistochemistry can be used as an adjunctive tool to rule out other diseases. Wide local excision is the standard treatment for resectable cutaneous apocrine carcinomas. Prophylactic lymphadenectomy should be considered as a treatment option given the high incidence of lymph node metastasis. Generally, cutaneous apocrine carcinomas are resistant to chemotherapy and radiation therapy; however, adjuvant radiotherapy is recommended for high-risk patients. Radiation or systemic therapy is administered to patients with distant metastases or recurrence. The systemic therapeutic options include cytotoxic chemotherapy, hormonal therapy, targeted therapy, and immune checkpoint inhibitors. Given the lack of data on clinical prognosis and standardized treatments, further studies are needed to improve our understanding of cutaneous apocrine carcinomas., (© The Author(s) 2024. Published by Oxford University Press. All rights reserved. For permissions, please e-mail: journals.permissions@oup.com.)

Purpose: To describe the clinical features of a conjunctival apocrine hidrocystoma that developed 6 decades after a strabismus surgery and review existing literature on apocrine hidrocystomas of the conjunctiva and caruncle., Methods: Case report and review of literature on conjunctival apocrine hidrocystomas., Results: A 71-year-old man with a history of strabismus surgery as a child presented with a cystic lesion on the nasal conjunctiva and caruncle for 1 year. Excision of the lesion showed a unilocular cavity lined by a double layer of cells with the hallmark finding of apical decapitations, confirming a diagnosis of apocrine hidrocystoma. Seven additional cases of conjunctival and caruncular apocrine hidrocystomas were reviewed. All cases presented after 50 year of age. Most cases presented nasally or within the caruncle and had a pigmented appearance. No other reported cases had a history of trauma or surgery. All cases were treated with surgical excision without recurrence., Conclusions: History of strabismus surgery or conjunctival trauma may lead to ectopic deposition of apocrine glands that may contribute to the formation of an apocrine hidrocystoma., Competing Interests: The authors have no funding or conflicts of interest to disclose., (Copyright © 2024 Wolters Kluwer Health, Inc. All rights reserved.)

Background: Apocrine carcinoma associated with Paget's disease is a rare malignancy that typically manifests in elderly individuals, predominantly affecting the geriatric population. It commonly arises in regions rich in apocrine glands and often exhibits an insidious onset, potentially requiring several years to be diagnosed., Case Presentation: An 80-year-old male was simultaneously diagnosed with scrotal apocrine carcinoma (showing Paget changes) and early-stage gastric cancer. Whole-genome exome sequencing confirmed these as independent malignancies with minimal genetic overlap, indicating that they were two primary tumors. The patient initially underwent successful surgery but experienced recurrence and metastasis. Treatment with capecitabine and paclitaxel showed promising responses, highlighting similarities between breast and apocrine carcinomas. Challenges were noted in the use of genetic testing and drug susceptibility assessments for treatment guidance. Notably, HER-2 expression in metastatic lesions, a trait of apocrine carcinoma, has remained unexplored due to negative HER-2 FISH results and a lack of available targeted therapies in China., Conclusion: Elderly patients often exhibit a lesser degree of aggressiveness toward treatment following a diagnosis of malignant tumors. It is imperative to carefully consider how to strike a balance between effective treatment and maintaining a satisfactory quality of life for these patients. This case underscores the complexity of treating coexisting rare cancers in older adults and emphasizes the need for personalized treatments and continued innovation in cancer therapy. The insights gained offer significant value in understanding and managing such rare cancer cases., (© 2024. The Author(s).)

Abstract: Mixed tumor of the skin (MTS) is a tumor characterized by folliculosebaceous-apocrine differentiation. Because of the wide range of histological variations, understanding the unique features of MTS can help improve diagnosis. This study describes the histopathological characteristics of MTS, mainly apocrine-type MTS (AMT), using 166 cases of AMT. We found that nodular aggregates of myoepithelial cells, mucinous changes in the stroma, and follicular differentiation were standard characteristic features of MTS. Among the cases studied, 67% showed prominent follicular germinative cells and 40% showed prominent lipomatous metaplasia in the stroma. These cases often pose difficulties for the diagnosis of AMT because of insufficient evidence of sweat glands or myoepithelial cell differentiation. This is the first study to examine how the histological features of AMT change as the tumor extends deeper into the dermis. We found that the proportion of AMT with folliculosebaceous differentiation and large lumina increased as it got deeper into the dermis. Histopathological diagnosis of MTS is vital because the clinical symptoms lack specificity. This study enhances our understanding of the histopathological characteristics of MTS., (Copyright © 2024 Wolters Kluwer Health, Inc. All rights reserved.)

Abstract: A 77-year-old Japanese man presented to our hospital with subcutaneous tumors of the right upper arm and axilla. A biopsy revealed a cutaneous adnexal tumor, showing apocrine differentiation, and axillary lymph node metastasis. After chemoradiotherapy to shrink the tumors, both lesions were resected. A resected specimen of the arm tumor showed a variegated histology: (1) a classic sebaceoma with an organoid pattern and sebocytes; (2) a sebaceous tumor with cellular atypia; (3) a papillotubular tumor showing a biphasic pattern of pale eosinophilic cells with apocrine differentiation and basaloid cells; and (4) an invasive adenocarcinoma with a micropapillary structure, reminiscent of an invasive micropapillary carcinoma of the breast. The axillary tumor was regressed. To our knowledge, this is the first reported case of an adnexal tumor of the skin with an invasive micropapillary structure arising in a sebaceous tumor., Competing Interests: The authors declare no conflicts of interest., (Copyright © 2024 Wolters Kluwer Health, Inc. All rights reserved.)

Adenomyoepithelioma(AME)of the breast is a rare condition, and comorbidity with carcinoma is even more unusual. Herein, we report a case of both AME and apocrine carcinoma in different breasts of a single patient. A 48-year-old woman presented to our clinic with a right breast tumor. Fine needle aspiration cytology(FNAC)was indeterminate and suspicious for both papilloma and non-invasive ductal carcinoma, but excisional biopsy indicated an AME. Immuno-histochemical staining showed EMA(+), AE1/3(+), and CK7(+)mammary duct cells and αSMA(+), CK5/6(+), and p63(+) myoepithelial cells. Six months later, the patient noticed a left breast tumor, and although FNAC indicated no malignancy, after 6 additional months, the tumor size had increased and a mammography revealed tumor microcalcification, suggesting malignancy. Vacuum-assisted biopsy revealed an apocrine carcinoma. The patient underwent partial mastectomy and sentinel node biopsy, followed by radiotherapy and chemotherapy. The post-surgical pathology was pT1pN0M0, Stage Ⅰ, triple- negative, and the patient was disease-free for 12 years postoperatively. To our knowledge, this is only the second case of AME and breast cancer in different breasts reported in Japan.

Abstract: Apocrine hidrocystomas are benign, cystic neoplastic lesions resulting from the apocrine secretory component of the sweat gland. They most commonly occur on the head and neck, with predilection to the periorbital area. Less frequent sites include the axilla, nipple, external auditory canal, foreskin, conjunctiva, lower lip, and fingers, among others. The authors report a unique case of a nail bed hidrocystoma in a 55-year-old woman, a site not previously described., Competing Interests: The authors declare no conflicts of interest., (Copyright © 2024 Wolters Kluwer Health, Inc. All rights reserved.)

Apocrine gland anal sac adenocarcinoma is an aggressive neoplasm, and surgery remains the treatment of choice, although it is controversial in advanced cases. The prognostic factors are not well established. Human Epidermal Growth Factor Receptor 2 (HER2) is a membrane protein related to tumorigenesis, whereas Ki67 is a nuclear protein related to cell proliferation. Both are potential prognostic markers and therapeutic targets. This study aimed to evaluate the expression of HER2 and Ki67 markers in canine apocrine gland anal sac adenocarcinoma. The tumor samples were divided into four groups: largest tumor diameter less than 2.5 cm, largest tumor diameter greater than 2.5 cm, metastatic lymph nodes, and control group of non-neoplastic anal sacs. Each contained 10 samples. Immunohistochemistry was performed to verify the expression of HER2 and Ki67 markers. Positive HER2 staining was observed in 45% of the neoplastic cases and negative HER2 staining in 100% of the control group. The Ki67 expression had a median of 25% in all groups, except for the control group, which had a median of 8%. The HER2 and Ki67 expression was present in apocrine gland anal sac adenocarcinoma, making them potential therapeutic targets. However, it was not possible to determine the clinical value of either marker.

Objectives: To report the histopathological diagnosis of both anal sacs in dogs undergoing bilateral anal sacculectomy for the treatment of unilateral apocrine gland anal sac adenocarcinoma and to compare the surgical complication rate associated with this procedure in this population with previously published literature., Materials and Methods: Records were retrospectively reviewed for dogs that underwent bilateral anal sacculectomy for the treatment of apparently unilateral apocrine gland anal sac adenocarcinoma, at a single institute between 2019 and 2023. Clinical staging, surgical treatment, histological findings, intra- and postoperative complications were evaluated., Results: Thirty-five dogs were included. Only five of 35 (14%) dogs were found to have histologically normal contralateral anal sacs. Non-neoplastic anal sac disease was found in 23 of 35 (66%) dogs and bilateral apocrine gland anal sac adenocarcinoma was seen in seven of 35 (20%) dogs. None of the dogs diagnosed with bilateral neoplasia had evidence of bilateral neoplasia before surgery despite a thorough work-up. Complications attributable to the primary tumour removal were seen in 9% of dogs intraoperatively and 14% of dogs postoperatively, commonly tumour capsule disruption and surgical site infection, respectively., Clinical Significance: Bilateral anal sac disease was diagnosed histologically in the majority of presumed normal anal sacs, with 20% of cases being found to have bilateral apocrine gland anal sac adenocarcinoma. The surgical complication rates of this cohort were comparable to those reported for unilateral anal sacculectomy alone. These findings promote and encourage the use of bilateral anal sacculectomy in cases of suspected unilateral anal sac neoplasia., (© 2024 The Authors. Journal of Small Animal Practice published by John Wiley & Sons Ltd on behalf of British Small Animal Veterinary Association.)

Background and Objectives : Secretory carcinoma of the breast is an uncommon histological subtype of breast cancer. There is little research on this entity and only a few larger studies, which lack consensus. We aim to report a particular apocrine differentiation in this subtype and ponder upon the clinical outcome of this case. Case presentation : We report the case of a 72-year-old female patient who presented to our hospital with a suspicious breast tumor. Core biopsy and mastectomy showed a low-grade breast carcinoma, a secretory subtype with apocrine differentiation. Immunohistochemistry confirmed both the secretory nature and the apocrine nature of the tumor cells. Surgical excision was considered curative and the patient is under long-term surveillance for any recurrences. Conclusions : There is very little research on the clinical behavior of secretory carcinomas with apocrine differentiation. The clinical outcome is unknown and, unfortunately, besides surgery, no other adjuvant treatments have shown efficacy. Further studies on long-term clinical progression are required for this rare entity.

Introduction: We report the clinical features and the management of two cases of orbital hidrocystoma in the setting of an enlarging orbital mass., Cases Description: A 48-year-old man presented with a mass in the right upper medial orbital quadrant, firmly attached to the supraorbital incisure. A 70-year-old man had a well demarcated lesion in the upper lateral orbital quadrant adherent to the lacrimal gland. There was no history of previous orbital trauma. In both cases histopathology confirmed a diagnosis of apocrine hidrocystoma. Following surgery, the first patient complained of mild hypoesthesia in the territory of the supraorbital nerve that resolved spontaneously within 3 weeks. Surgery was uneventful in the other patient. No recurrence was seen during the follow up., Conclusions: Apocrine hidrocystomas have been rarely described in the orbit, but should be considered in the differential diagnosis of orbital cystic masses. Recurrence is rare following complete surgical excision., Competing Interests: Declaration of conflicting interestsThe author(s) declared no potential conflicts of interest with respect to the research, authorship, and/or publication of this article.

Background: Apocrine cystadenoma is a rare, benign adenomatous cystic neoplasm, the pathogenesis of which is not fully understood. We sought to characterize the clinical, dermatoscopic, and histopathologic features of apocrine cystadenoma and its relationship to hidrocystoma., Methods: We retrospectively analyzed cases of apocrine cystadenoma and hidrocystoma retrieved from the dermatopathology laboratory information system., Results: Of the 350 cases apocrine cystic lesions, 13 cases of apocrine cystadenomas met the inclusion criteria. The age ranged from 20 to 84 years with an average of 64 years. They were long-standing (duration 3-15 years), slow-growing, large tumors usually found on the scalp. Dermatoscopy accentuated translucent light to dark blue color and prominent vessels that were present more at the periphery. All lesions were multilocular with columnar to cuboidal lining and decapitation secretion. A large portion of the lesion consisted of a simple nonproliferative epithelial lining, identical to that observed in apocrine hidrocystomas, while the proliferative adenomatous component made up a smaller portion with two patterns: (1) tubular proliferation, which either protruded into the cystic cavity or expanded outward peripherally, or (2) papillary projections, which were multiple layers thick with fibrovascular core, sometimes accompanied by tubular proliferation. Immunohistochemical stains showed strong staining for p40 and a sparse number of cells stained for Ki-67 and p53., Conclusions: The long duration of the lesion and the large areas of simple apocrine epithelial lining suggest that apocrine cystadenomas arise from long-standing apocrine hidrocystomas. However, the retrospective nature of the study from a single institution is a limitation., (© 2023 John Wiley & Sons A/S. Published by John Wiley & Sons Ltd.)

Apocrine carcinoma is an extremely rare malignant cutaneous neoplasm that usually arises in areas with a high density of apocrine glands. Diagnosis can be challenging as tumours share histological and immunophenotypic characteristics with them. At first evaluation, the disease is often assumed to be benign. There have been approximately 100 reports of apocrine neoplasms in the literature. A 48-year-old male presented with a right axillary mass which increased in size over a period of 2 years. The patient was reported to have had ayurvedic therapy, but his swelling remained unchanged. Axillary lymph nodes were palpable. USG axilla suggested a well-defined fungating solid isoechoic lesion. USG neck did not reveal any abnormality. The mass was surgically excised as a whole by removing the overlying skin with margins and lymph node excision. The patient was diagnosed with primary apocrine carcinoma after surgical excision. The differentials include adenocarcinoma of breast and prostate and apocrine adenoma. There are no established standards for the care of this form of carcinoma due to its rarity and the absence of clinical studies. A literature evaluation and further reporting will aid in developing diagnostic standards and the most efficient treatment options., Competing Interests: No competing interests were disclosed., (Copyright: © 2023 Naseri DS et al.)

An 83-year-old woman experienced the slow enlargement of a right lower eyelid mass. Histopathologic examination of the excised tissue showed a mucin-filled cystic tumor emanating from an apocrine bilayer that displayed bleb-like apocrine decapitation secretion. The outer flattened myoepithelial layer of the bilayer reacted with immunohistochemical stains for smooth muscle actin and calponin. In foci, the tumor exhibited a cribriform architecture with small pockets of mucin. Tumor cells were reactive for cytokeratin 7, Gross Cystic Disease Fluid Protein 15 (BRST-2), estrogen and progesterone receptors, androgen receptors, mammaglobin, epithelial membrane antigen, and GATA3. Ki67 showed a very low proliferation fraction. The lesion exemplifies the fourth instance of an eyelid apocrine cystadenoma in the literature., Competing Interests: The authors have no conflicts of interest to disclose., (Copyright © 2023 The American Society of Ophthalmic Plastic and Reconstructive Surgery, Inc.)

Apocrine gland anal sac adenocarcinoma (AGASACA) is a highly relevant disease in dogs, with a high rate of lymph node (LN) metastasis during the course of disease. A recent study showed that risk for death and disease progression was significantly associated with primary tumour size less than 2 and 1.3 cm, respectively. The objective of this study was to report the proportion of dogs that have primary tumours less than 2 cm in diameter, that are diagnosed with LN metastasis at presentation. This was a single site retrospective study of dogs that underwent treatment for AGASACA. Dogs were included if physical examination primary tumour measurements were available, abdominal staging was performed, and confirmation of abnormal lymph nodes by cytology or histology was done. Over a 5-year period, 116 dogs were included for review with 53 (46%) having metastatic LN at presentation. The metastatic rate for dogs with primary tumours <2 cm was 20% (9 of 46 dogs) compared to 63% (44 of 70 dogs) in dogs with primary tumours ≥2 cm. The association between tumour size group (<2 vs. ≥2 cm) and the presence of metastasis at presentation was significant (P < .0001) with an OR of 7.0 (95% CI: 2.9-15.7). Primary tumour size was significantly associated with LN metastasis at presentation but the proportion of dogs that presented with LN metastasis in the <2 cm group was relatively high. This data suggests that dogs with small tumours may still have aggressive tumour biology., (© 2023 The Authors. Veterinary and Comparative Oncology published by John Wiley & Sons Ltd.)

Objective: To evaluate short- and long-term outcomes for dogs undergoing anal sacculectomy for massive (> 5 cm) apocrine gland anal sac adenocarcinoma (AGASACA)., Animals: 28 client-owned dogs with massive AGASACA., Procedures: A retrospective multi-institutional study was performed. Pre-, intra-, and post-operative data was collected, and variables were statistically analyzed for associations with progression-free interval (PFI) and overall survival (OS)., Results: At the time of anal sacculectomy, 19 (68%) dogs underwent concurrent iliosacral lymph node extirpation, including 17 of 18 (94%) dogs with suspected nodal metastasis preoperatively. Five (18%) dogs experienced grade 2 intraoperative complications. Ten (36%) dogs experienced postoperative complications, including 1 grade 3 and 1 grade 4 complication. No dogs had permanent fecal incontinence, tenesmus, or anal stenosis. Nineteen dogs received adjuvant chemotherapy, radiation, or both. Local recurrence occurred in 37% of dogs. Dogs with lymph node metastasis at surgery were more likely than dogs without metastasis to develop new/progressive lymph node metastasis (10/17 [59%] vs 0/10 [0%]; P = .003) and distant metastasis (7/17 [41%] vs 0/10 [0%]; P = .026). Median PFI was 204 days (95% CI, 145 to 392). Median OS was 671 days (95% CI, 225 to upper limit not reached). Nodal metastasis at the time of surgery was associated with shorter PFI (P = .017) but not OS (P = .26). Adjuvant therapy was not associated with outcome., Clinical Relevance: Dogs with massive AGASACA experienced prolonged survival following anal sacculectomy despite a high incidence of local recurrence and metastasis. Lymph node metastasis at the time of surgery was a negative prognostic indicator for PFI but not OS.

Abstract: Mucinous metaplasia (goblet cell type) is exceptionally rare in the skin. This is the second case of apocrine papillary hidrocystoma with mucinous metaplasia (goblet cell type) and a review of the literature exploring the significance and frequency of mucinous metaplasia with goblet cells in nongenital skin. The patient is an elderly man who presented with a blue-pigmented nodule on the scalp that was clinically suggestive of an atypical nevus. Histologically, the lesion was composed of a simple cyst of cuboidal cells with decapitation secretion and mucinous metaplasia with goblet cells. Papillary formation was identified in the cysts. Most cases of cutaneous mucinous metaplasia have been reported on genital skin, usually after chronic inflammation of the area. This type of mucinous metaplasia is categorized as benign mucinous metaplasia of the genitalia (BMM) and is believed to be unrelated to apocrine glands owing to the different histologic features and absence of apocrine differentiation by immunohistochemistry. Mucinous metaplasia (goblet cell type) has been previously reported in benign adnexal tumors (eccrine acrospiroma/hidroadenoma, mixed tumor, and syringocystadenoma papilliferum) and in malignant tumors (apocrine hidradenocarcinoma and squamous cell carcinoma). To date, mucinous metaplasia has not been identified in the histologically normal apocrine glands., Competing Interests: This manuscript has not been published previously and is not currently under review for publication elsewhere. There are no conflicts of interest to disclose at the time of writing. Please contact us with any questions or concerns, and thank you for your consideration., (Copyright © 2023 Wolters Kluwer Health, Inc. All rights reserved.)

Primary cutaneous cribriform apocrine carcinoma (PCCAC) is an exceedingly rare sweat gland carcinoma. Clinically, it most often presents as a singular, asymptomatic nodule or cyst on the extremities of middle-aged patients and follows an indolent course. Both visceral and cutaneous cribriform tumors exist in nature. While a cribriform pattern is well recognized in tumors of visceral organs, there is a paucity in the literature on the defining characteristics for primary cutaneous tumors. Consensus regarding diagnostic criteria, etiology, and management protocols has yet to be achieved. We conducted an extensive literature review using pre-determined search criteria, resulting in 12 identified case reports and series on PCCAC that were subsequently analyzed. All data were compiled to provide a comprehensive update on the existing information regarding clinical presentation, histopathology, and management of reported PCCACs, as well as differential diagnosis, controversial issues, and recommendations for future considerations., (© 2022. This is a U.S. government work and not under copyright protection in the U.S.; foreign copyright protection may apply.)

Apocrine gland anal sac adenocarcinoma (AGASAC) is a relatively uncommon tumor in the dog and comprises approximately 17% of perianal malignancies; however, it is one of the most common causes of paraneoplastic hypercalcemia. Clinical signs in affected dogs most commonly are associated with mechanical obstruction caused by the primary tumor or enlarged regional metastatic lymph nodes and the effects of paraneoplastic hypercalcemia when present. Surgical excision of the primary tumor and metastasectomy of affected locoregional lymph nodes is the preferred initial treatment option for most dogs, although radiation therapy and adjuvant chemotherapy are commonly incorporated into multi-modality treatment plans. A significant role for the use of adjuvant chemotherapy has not been clearly demonstrated. Prolonged survival times are possible, especially for dogs with smaller primary tumors and for dogs that undergo further treatments for recurrent disease. In this article, we review the clinical signs, diagnosis, staging, treatment, and prognosis of AGASAC in the dog., (Copyright © 2022. Published by Elsevier Inc.)

Objective: To report intraoperative and immediate postoperative complications associated with removal of metastatic iliosacral lymph nodes in dogs with apocrine gland anal sac adenocarcinoma., Animals: There were 136 client-owned dogs in the study., Procedure: Retrospective multi-institutional study. The database of collaborating institutions was searched for dogs with metastatic apocrine gland anal sac adenocarcinoma that underwent lymphadenectomy for removal of one or more iliosacral lymph nodes. Information of signalment, hematological abnormalities, abdominal computed tomography or ultrasound findings, number and size of enlarged lymph nodes, intraoperative and postoperative complications, treatment and outcome were collected., Results: The overall complication rate associated with metastatic iliosacral lymphadenectomy was 26.1%. The only intraoperative complication recorded was hemorrhage and was reported in 24 (17.6%) surgeries, 11 (45.8%) of which received a blood transfusion. Postoperative complications were reported in 10.4% of surgeries, and included edema formation ( n = 4, 2.6%), unilateral or bilateral paraparesis ( n = 4, 2.6%), hypotension ( n = 3, 2.0%), surgical site infection ( n = 2, 1.3%), abdominal incision dehiscence ( n = 1, 0.6%), urinary incontinence ( n = 1, 0.6%), and death ( n = 1, 0.6%). The size of the iliosacral lymph nodes was significantly associated with a greater risk of complications, hemorrhage, and the need of transfusion during lymphadenectomy for metastatic apocrine gland anal sac adenocarcinoma., Conclusion: Complications associated with iliosacral lymphadenectomy for metastatic apocrine gland anal sac adenocarcinoma are relatively common and mostly relate to hemorrhage. These complications are significantly associated with the size of the extirpated metastatic lymph nodes., Clinical Relevance: This retrospective study provides information for the clinician regarding the potential surgical complications for extirpation of metastatic iliosacral lymph nodes. These complications, although not common, can be severe and should be discussed with owners before surgery., (Copyright and/or publishing rights held by the Canadian Veterinary Medical Association.)

Abstract: Moll gland is a modified tubular-shaped apocrine sweat gland, which is located on the margin of the eyelid. Moll glands are also known as ciliary glands. The function of these glands was not well known for a long time. However, based on the different studies, it was proved that Moll glands are active from birth and have local immunologic function producing immunoglobulin A. We present a case of Moll adenocarcinoma, a type of apocrine carcinoma, arising from the right upper eyelid of a 57-year-old man. Although Moll gland cysts are frequently seen, this type of adnexal malignancy is extremely uncommon. These tumors can have variable presentation and behavior from less invasive forms to highly malignant metastatic recurrent lesions., Competing Interests: The authors declare no conflicts of interest., (Copyright © 2022 Wolters Kluwer Health, Inc. All rights reserved.)

Apocrine hidrocystomas are benign cystic tumors derived from apocrine sweat glands; they are most commonly located in the skin of the head and neck regions. Ophthalmic occurrences typically appear at the lash line and canthi of the eyelid, although rare instances have been described in the conjunctiva, caruncle, and orbit. The authors illustrate an exceptional instance of a mobile episcleral cyst in a 12-year-old girl that developed about 2 years following strabismus surgery. The cyst was located anterior to the insertion of the left medial rectus and was excised in response to the patient's complaints of irritation. Histopathology of the excised specimen displayed an empty cyst lined by a double layer of cuboidal epithelium with the inner layer exhibiting apical decapitation secretion. Confirmatory immunohistochemistry demonstrated reactivity of both layers with CK7 and the outer myoepithelial layer with D2-40. Postoperative and traumatic cysts formed after interruption of the bulbar conjunctiva are usually conjunctival cysts lined by stratified squamous nonkeratinizing epithelium., Competing Interests: The authors have no conflicts of interest to disclose., (Copyright © 2022 The American Society of Ophthalmic Plastic and Reconstructive Surgery, Inc.)

Background: Sebaceous carcinoma and sweat gland carcinoma (malignant tumours with apocrine and eccrine differentiation) are rare malignant adnexal tumours that differentiate toward sebaceous glands and eccrine and apocrine glands, respectively. Because of the rarity of these malignancies, standard treatments for advanced disease have yet to be established. The outcomes of patients with systemic metastasis remain poor, highlighting the need for novel treatment strategies. Nectin cell adhesion molecule 4 (NECTIN4) and its antibody-drug conjugate, enfortumab vedotin, have attracted attention as potential treatments for solid tumours., Objectives: To examine the potential use of NECTIN4-target therapy for sebaceous and sweat gland carcinoma., Materials & Methods: We immunohistochemically investigated NECTIN4 expression in 14 sebaceous carcinoma samples and 18 sweat gland carcinoma samples, and examined whether NECTIN4-targeted therapy could be applied to these cancers., Results: We found strong and frequent expression of NECTIN4 in both cancers. All tumours exhibited positive staining at least in a part of the lesion, and the mean H-score, a semiquantitative score ranging from 0 to 300, was 259.4 for sebaceous carcinoma and 253.1 for sweat gland carcinoma., Conclusion: Our results suggest that both sebaceous carcinoma and sweat gland carcinoma could be potentially treated with NECTIN4-targeted antibody-drug conjugates, such as enfortumab vedotin.

Invasive apocrine carcinoma of the breast is a rare entity with an incidence of 3 or 4 cases per million women. Although apocrine breast cancers may have an aggressive clinical presentation, the 7-year cancer survival rate is the same as non-apocrine cancers. The prognosis of IAC is currently determined by conventional factors such as grade, tumor size, and nodal status. Targeted AR therapy is increasingly adopted with some positive results in clinical trials. This research may result in the development of a tailored treatment for these unusual and rare cancers., (Copyright © 2021 Elsevier Inc. All rights reserved.)

Advancements within the field of veterinary surgical oncology are constantly presenting themselves, especially with continued development of comprehensive cancer programs. With the use of more advanced imaging techniques within veterinary medicine, tumor staging is improving and techniques novel to veterinary medicine are being evaluated for potential clinical application. Recommended tumor staging and treatment approach for apocrine gland anal sac adenocarcinoma in dogs has evolved, with the anticipation of good long-term patient outcomes. Preoperative staging for mast cell tumors and recommendations for surgical margins to obtain for wide surgical excision is being reassessed by surgeons., Competing Interests: Disclosure The author has nothing to disclose., (Copyright © 2021 Elsevier Inc. All rights reserved.)

Rationale: Apocrine carcinoma is a rare malignant sweat gland tumor that has been reported in approximately 200 cases. This tumor usually occurs in the axilla, but in rare cases, it can also develop in the scalp. In the present work, we report 2 cases of cutaneous apocrine carcinoma of the scalp., Patient Concerns: Two men visited our outpatient clinic with recurrence of tumor after undergoing surgery for scalp tumor at another hospital., Diagnoses: Brain magnetic resonance imaging of a 56-year old man showed the presence of a 5.0 × 4.5 × 4.4 cm scalp mass in the right parietal region, invading the skull and dura mater and a 2.2 × 2.0 × 0.7 cm bony mass without any skin lesions right next to the scalp mass. Neck magnetic resonance imaging of a 76-year-old man revealed the presence of a well-defined oval mass in the subcutaneous layer of the left occipital scalp and 2 enlarged lymph nodes in the left neck. Definite diagnoses were made postoperatively. The patients were diagnosed with cutaneous apocrine carcinoma. The diagnosis was confirmed through histopathological and immunohistochemical staining tests., Interventions: The tumors were removed with a wide safety margin and reconstructive surgery was performed., Outcomes: Additional radiotherapy or chemotherapy was performed. Follow-up more than 6 months revealed no recurrence or metastasis., Lessons: If accurate diagnosis and treatment had taken place at the initial stages of the primary cutaneous apocrine carcinoma, it would have been possible to prevent recurrence and intracranial invasion. As recurrent primary cutaneous apocrine carcinoma can become aggressive and difficult to treat, even a small mass on the scalp must be evaluated carefully and treated properly., Competing Interests: The authors have no funding and conflicts of interest to disclose., (Copyright © 2022 the Author(s). Published by Wolters Kluwer Health, Inc.)

Abstract: Apocrine hamartoma is a rare benign neoplasm. The histology is characterized by an excess of apocrine glands located predominantly in the reticular dermis. Pigmented apocrine hamartoma represents a histopathological variation of apocrine hamartoma containing tubules and linear cysts covered by apocrine cells on the inside with melanin and on the outside with myoepithelial cells. At this time, 4 cases of this pathology have been described. This case report aims to present a case of pigmented apocrine hamartoma of the vulva in a young patient, emphasizing that while occurrence is rare, it must be considered when diagnosing a pigmented lesion of the vulva in young patients., Competing Interests: The authors declare no conflicts of interest., (Copyright © 2021 Wolters Kluwer Health, Inc. All rights reserved.)

Apocrine hidrocystoma (AH) is a benign cystic proliferation of apocrine sweat glands that classically presents as a slow-growing nodule on the face, especially in the periorbital region. Histopathological evaluation is required to definitively diagnose an apocrine hidrocystoma. Previous studies have described apocrine hidrocystomas in unusual locations. However, the authors have identified only two reported cases of apocrine hidrocystoma in the postauricular region. We present a third case of a postauricular hidrocystoma in a 26-year-old woman, as well as a brief review of the dermoscopic findings of apocrine hidrocystomas in the existing literature.

Rationale: Tubular apocrine adenoma (TAA) is a very rare benign neoplasm of the apocrine gland. The typical anatomical locations are mostly hair-bearing areas, where normal apocrine glands are abundant., Patient Concerns: We report the case of a 40-year-old patient with a tubular apocrine adenoma on a non-hair-bearing area., Diagnoses: Ultrasonography showed a 0.4-cm-sized hypoechoic nodule in the subcutaneous plane of the left palm at the fourth carpometacarpal joint level., Interventions: Surgical resection was performed and histopathological examination revealed lobules of well-differentiated dilated tubular structures at the dermis level., Outcomes: At 1 year of postoperative follow-up, the patient was completely recovered without signs of recurrence., Lessons: Diagnosis of TAA can be misleading due to its unusual location and inconspicuous appearance. Immunohistochemistry for epithelial membrane antigen and gross cystic disease fluid protein-15 is crucial for the proper diagnosis. Complete excision is recommended to prevent recurrence., Competing Interests: The authors have no conflicts of interest to disclose., (Copyright © 2021 the Author(s). Published by Wolters Kluwer Health, Inc.)

Carcinoma with apocrine differentiation is an androgen receptor (AR)-positive subset of triple-negative breast carcinomas. In addition to carcinoma with apocrine differentiation, other AR-positive triple-negative breast carcinomas occur, albeit less frequently. We found that α-methylacyl-CoA racemase (AMACR), also known as P504S, is overexpressed in carcinoma with apocrine differentiation and non-neoplastic apocrine metaplasia. We aimed to evaluate AMACR as a possible marker of carcinoma with apocrine differentiation. We immunohistochemically examined the expression of AMACR in carcinoma with apocrine differentiation and nonapocrine carcinomas and compared it with that of gross cystic disease fluid protein-15 (GCDFP-15). In total, 212 breast carcinomas were evaluated: 39 carcinomas with apocrine differentiation, 28 ductal carcinomas in situ with apocrine morphology (ADCIS), and 145 nonapocrine breast carcinomas. AMACR was expressed in 38 of 39 (97.4%) carcinomas with apocrine differentiation and in 27 of 28 (96.4%) ADCIS, consistent with the expression of GCDFP-15. However, in nonapocrine carcinomas, AMACR expression was observed in 32 of 145 (22.0%) lesions, whereas GCDFP-15 expression was observed in 91 of 145 (62.7%) lesions. For carcinoma with apocrine differentiation, AMACR was as sensitive as GCDFP-15 (both 97.1%) but more specific (77.9% versus 37.2%). In selected cases, AMACR messenger RNA (mRNA) levels were quantitatively determined relative to that of TATA-binding protein mRNA, and they comprised 5.23, 1.33, and 0.60 for carcinomas with apocrine differentiation, nonapocrine carcinomas, and normal breast tissue, respectively. CONCLUSION: Our findings demonstrate that AMACR expression may be used for differentiating carcinoma with apocrine differentiation from nonapocrine carcinomas and indicate that AMACR is a more sensitive carcinoma with apocrine differentiation marker than GCDFP-15., (Copyright © 2021 Elsevier Inc. All rights reserved.)

Pure invasive papillary carcinoma (IPC) is a rare subtype of breast carcinoma with good prognosis compared with classical invasive breast carcinoma (IBC) of no special type. The majority of IPC are estrogen receptor and progesterone receptor (ER/PR) positive and HER2 negative (luminal A-like). We report the case of a 72-year-old women who was referred to the Senology Clinic for a routine workup following surgery for an intraductal papilloma. The core needle biopsy (CNB) showed a lesion mainly composed of irregular papillae and micropapillae with apocrine epithelial cells of low-to-intermediate nuclear grade, without a myoepithelial cell layer within the papillae and at the periphery, as demonstrated with multiple immunostains. The diagnosis of apocrine papillary lesion of uncertain malignant potential was made. The subsequent lumpectomy showed an IBC with the same cyto-architectural features as the CNB. In addition, lymphovascular invasion and papillary/micropapillary apocrine in situ lesion were noted. Notably, the tumor was ER/PR and HER2 negative and strongly positive for androgen receptor. A final diagnosis of mixed apocrine papillary/micropapillary carcinoma with triple-negative status was made. To the best of our knowledge, this is the first report of an IBC with these features. Breast pathologists should be aware of this entity when dealing with CNB samples characterized by a complex papillary lesion with apocrine atypia that lacks a myoepithelial cell layer on multiple immunostains. These lesions should be classified at least as of uncertain malignant potential based on the cyto-architectural features prompting a surgery for removal.

Adnexal tumors of the skin are a rare group of benign and malignant neoplasms that exhibit morphological differentiation toward one or more of the adnexal epithelium types present in normal skin. Tumors deriving from apocrine or eccrine glands are highly heterogeneous and represent various histological entities. Macroscopic and dermatoscopic features of these tumors are unspecific; therefore, a specialized pathological examination is required to correctly diagnose patients. Limited treatment guidelines of adnexal tumor cases are available; thus, therapy is still challenging. Patients should be referred to high-volume skin cancer centers to receive an appropriate multidisciplinary treatment, affecting their outcome. The purpose of this review is to summarize currently available data on pathogenesis, diagnosis, and treatment approach for apocrine and eccrine tumors.

American Cocker Spaniels (ACSs) develop aural ceruminous gland hyperplasia and ectasia more often than dogs of other breeds. Data on the cause and development of these breed characteristic histopathological changes are lacking. We performed video-otoscopic examinations and dermatological work-up on 28 ACSs, obtained aural biopsies from each dog and assessed the statistical associations between the presence of ceruminous gland hyperplasia and ectasia and disease history, clinical or microbiological findings and underlying cause of otitis externa (OE). Histological lesions of ceruminous gland hyperplasia and ectasia were observed in aural biopsies from 6/13 clinically healthy ears and 13/15 ears with OE from 19/28 examined dogs. Nine of 28 dogs had histologically normal ceruminous glands (odds ratio [OR] 6.2, 95% confidence interval [CI] 1.1-36.6). Bacterial growth in microbiological culture of aural exudate (OR 14.1, 95% CI 2.1-95.3) was associated with ceruminous glandular changes, whereas previous history of OE, cutaneous findings or underlying allergies were not. Pedigree analysis and a genome-wide association study (GWAS) were performed on 18 affected and eight unaffected dogs based on histopathological diagnosis. While the GWAS indicated a tentative, but not statistically significant, association of ceruminous gland hyperplasia and ectasia with chromosome 31, a larger cohort is needed to confirm this preliminary result. Based on our results, ceruminous gland hyperplasia and ectasia may also precede clinical signs of OE in ACSs and a genetic aetiological component is likely Further studies with larger cohorts are warranted to verify our preliminary results., (Copyright © 2021 The Authors. Published by Elsevier Ltd.. All rights reserved.)

Triple negative breast cancers (TNBC) are a morphologically and genetically heterogeneous group of breast cancers with uncertain prediction of biological behavior and response to therapy. Epithelial to mesenchymal transition (EMT) is a dynamic process characterized by loss of typical epithelial phenotype and acquisition of mesenchymal characteristics. Aberrant activation of EMT can aggravate the prognosis of patients with cancer, however, the mechanisms of EMT and role of microRNAs (miRNAs) in EMT activation is still unclear. The aim of our study was to analyze miRNA expression within areas of TNBCs with cellular morphology that may be related to the EMT process and discuss possible associations. Out of all 3953 re-examined breast cancers, 460 breast cancers were diagnosed as TNBC (11.64%). With regard to complete tumor morphology preservation, the tissue samples obtained from core-cut biopsies and influenced by previous neoadjuvant therapy were excluded. We assembled a set of selected 25 cases to determine miRNA expression levels in relation to present focal spindle cell and apocrine cell morphology within individual TNBCs. We used descriptive (histological typing and morphology), morphometric, molecular (microdissection of tumor and non-tumor morphologies, RNA isolation and purification, microchip analysis) and bioinformatic analysis (including pathway analysis). The results were verified by quantitative real-time PCR (RT-qPCR) on an extended set of 70 TNBCs. The majority of TNBCs were represented by high-grade invasive carcinomas of no special type (NST) with medullary features characterized by well-circumscribed tumors with central necrosis or fibrosis and frequent tendency to spindle-cell and/or apocrine cell transformation. Apocrine and spindle cell transformation showed a specific miRNA expression profile in comparison to other tumor parts, in situ carcinoma or non-tumor structures, particularly down-regulated expression of hsa-miRNA-143-3p and hsa-miRNA-205-5p and up-regulated expression of hsa-miR-22-3p, hsa-miRNA-185-5p, and hsa-miR-4443. Apocrine cell tumor morphology further revealed decreased expression of hsa-miR-145-5p and increased expression of additional 14 miRNAs (e.g. hsa-miR-182-5p, hsa-miR-3135b and hsa-miR-4417). Pathway analysis for target genes of these miRNAs revealed several shared biological processes (i.e. Wnt signaling, ErbB signaling, MAPK signaling, endocytosis and axon guidance), which may in part contribute to the EMT and tumor progression. We provide the first miRNA expression profiling of specific tissue morphologies in TNBC. Our results demonstrate a specific miRNA expression profile of apocrine and spindle cell morphology which can exhibit a certain similarity with the EMT process and may also be relevant for prognosis and therapy resistance of TNBC.

Long regarded as ectopic or supernumerary breast tissue, anogenital mammary-like glands (AGMLG) are now considered a normal constituent of the anogenital area. AGMLG are presumed to be the origin for various benign and malignant lesions. Changes in AGMLG compatible with usual ductal hyperplasia and atypical ductal hyperplasia considered as precursor lesions and its presence in specimens can be explained by their role in the pathogenesis of primary extramammary Paget disease. In this report, we presented four cases of invasive squamous cell carcinoma accompanied by non-neoplastic atypical changes in ductal portions of AGMLG compatible with atypical ductal hyperplasia in breast adjacent to the carcinoma. This is a reactive phenomenon similar to that seen in apocrine/eccrine glands adjacent to squamous cell carcinoma. In a limited biopsy specimen, these areas should not be mistaken for adenocarcinoma., Competing Interests: The authors declare no conflict of interest., (Copyright © 2020 by the International Society of Gynecological Pathologists.)

Background: Electrochemotherapy (ECT) combines the administration of anticancer drugs with the delivery of electric pulses, thus increasing the drug uptake through the cell membranes, resulting in increased efficacy., Aim: The aim of our study was to describe the tolerability and efficacy of ECT alone or in association with other treatment modalities for the management of apocrine gland anal sac adenocarcinoma (AGASAC)., Methods: Medical records of dogs with a diagnosis of AGASAC that were treated with ECT alone or in combination with surgery/chemotherapy were retrospectively evaluated. Each dog received 20 mg/m 2 of bleomycin intravenously. Based on the clinician's decision, the primary tumor or tumor bed was also infiltrated with cisplatin at the dose of 0.5 mg/cm 2 . Trains of permeabilizing biphasic electric pulses were then applied under general anesthesia., Results: Ten dogs were enrolled in the study. Of those 10 dogs, only one received ECT for treatment of microscopic local disease, while in six cases ECT was the only treatment modality. In three dogs, ECT was followed by systemic medical treatment. Six dogs (60%) had a partial response (PR), three dogs (30%) had stable disease, and one dog treated for microscopic disease did not show any sign of local relapse for 305 days after treatment, being still alive and in complete remission at the time of writing this article. The median time to progression was 303 days and the median survival time was 365 days. The treatment was well tolerated and local side effects were minimal. No systemic effects were documented., Conclusion: This preliminary study suggests that ECT may be beneficial for dogs with AGASAC and could be a useful addition to the current therapeutic options in consideration of its low cost, limited toxicity, and ease of administration., Competing Interests: Enrico P. Spugnini and Alfonso Baldi are the stockholders of Biopulse S.r.l.