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White epidermoid cysts are rare intra-cranial lesions with an intrinsic brainstem location, though still rare. The location of the tumour poses radiological confusion and a therapeutic dilemma. Neuroimaging techniques like MRI with diffusion tensor imaging (DTI) in this case proved a useful tool in ruling out other pathologies at this location with certain morphologic similarities. MRI findings indicated a bilobed intra-axial lesion with heterogenous signal intensities on T1 and T2 weighted images. DTI showed splaying of cortico-spinal tracts. The intraoperative cystic nature of the lesion was established, followed by a biopsy report confirming the lesion to be a white epidermoid cyst., Competing Interests: Competing interests: None declared., (© BMJ Publishing Group Limited 2024. No commercial re-use. See rights and permissions. Published by BMJ.)

We report an unusual case of an elderly man presenting with formation and rupture of an epidermal inclusion cyst at the level of an implantable cardiac defibrillator (ICD) pocket. The lesion appeared 2 years after ICD implantation, mimicking a decubitus or a pocket infection. Surgical revision showed no signs of infection of the pocket, but the pedunculated lesion was rooted in the subcutaneous tissue, whit an implant base external to the ICD pocket, which was removed and analyzed histologically, confirming the diagnosis of epidermal inclusion cyst. The pathophysiological mechanism of cyst formation is discussed. This case highlights the importance of an increased attention to lesions that mimic infections of a cardiac implantable electronic device pocket, thus preventing unnecessary complete removal of the device system.

Squamous cell carcinoma of the orbit is uncommon as there is no squamous epithelium in the orbit. Thus, mechanistically squamous cell carcinoma of the orbit most commonly arises from a cutaneous lesion. Although orbital epidermoid cysts are thought to have very low malignant potential, these lesions possess squamous epithelium and theoretically can undergo malignant transformation. Here, the authors present the case of a 63-year-old woman who presented with a 3-month history of diplopia and forehead tenderness with an orbital extraconal lesion on MRI consistent with a ruptured epidermoid cyst. Six months following resection, she suddenly experienced new-onset left upper eyelid ptosis, recurrent diplopia, and left orbital pain. MRI revealed a recurrence of the left orbital mass. Left anterior orbitotomy and biopsy revealed cystic squamous cell carcinoma. This case appears to demonstrate a very rare malignant transformation of an epidermoid cyst to cystic squamous cell carcinoma., Competing Interests: The authors have no conflicts of interest to disclose., (Copyright © 2024 The American Society of Ophthalmic Plastic and Reconstructive Surgery, Inc.)

Introduction: Epidermoid cyst in an intrapancreatic accessory spleen (ECIPAS) is an exceedingly rare pancreatic lesion that is always mistakenly suspected of malignancy preoperatively., Case Summary: A 25-year-old male patient incidentally found a giant mass in the left upper abdomen neighboring the hilum of the spleen. The patient denied any obvious discomfort. Except for a slightly elevated carbohydrate antigen 19-9 (CA-19-9, 43.5 U/mL), no abnormal laboratory test results were found. Contrast-enhanced computed tomography, conventional ultrasound, and magnetic resonance imaging were performed. The patient received a laparoscopic distal pancreatectomy. The final pathology showed ECIPAS. The postoperative course was uneventful and no signs of recurrence during 2 years of follow-up., Discussion: For an incidental pancreatic cystic lesion, ECIPAS should be considered in the differential diagnosis. ECIPAS may mimic pancreatic cystadenoma. Imaging follow-up or surgical removal may be useful for the exclusion of malignant risks in ECIPAS., Competing Interests: The authors declare no conflict of interest., (Copyright © 2024 Wolters Kluwer Health, Inc. All rights reserved.)

An uncommon case of an intratarsal keratinous cyst at the lid margin is described in a 73-year-old Asian man using long-term antiglaucoma eye drops. There was no history of trauma or surgery of the upper eyelid. A yellow solid mass attached to the tarsal plate had been located there for about 3 years. It imitated a sebaceous gland carcinoma or steatocystoma simplex. Excision biopsy showed cystic formation and leaked yellow creamy substance without hair. Histopathological and immunological findings helped make the diagnosis of an intratarsal keratinous cyst. To the best of the authors' knowledge, this is the first case report of an intratarsal keratinous cyst at the lid margin., Competing Interests: The authors have no financial or conflicts of interest to disclose., (Copyright © 2024 The Author(s). Published by Wolters Kluwer Health, Inc. on behalf of the American Society of Ophthalmic Plastic and Reconstructive Surgery, Inc.)

Folliculosebaceous cystic hamartoma (FSCH) is a rare cutaneous hamartoma comprising epithelial and mesenchymal components. It typically appears as slow-growing, skin-coloured nodules on the face and scalp. We report a case of a mid-forties male with a 4 mm nodule on his left temple, initially thought to clinically represent an epidermal inclusion cyst (EIC). Excisional biopsy results identified the lesion as FSCH, characterised by its unique dilated infundibulocystic configuration with radiating sebaceous lobules and associated mesenchymal elements. FSCH can be misdiagnosed for EIC due to similar clinical presentations but has distinct histological features. Surgical excision is the standard treatment, and the patient has remained recurrence-free since the procedure. This case underscores the importance of considering FSCH in the differential diagnosis of particularly facial and scalp nodules., Competing Interests: Competing interests: None declared., (© BMJ Publishing Group Limited 2024. No commercial re-use. See rights and permissions. Published by BMJ.)

Abstract: Epidermoid splenic cyst is a rare benign tumour in children, accounting for 10% of all cystic lesions of the spleen and is the most common diagnosis of non-parasitic splenic cysts. Its discovery could be incidental or happen after an imaging workup for a mass or abdominal pain. Since total splenectomy exposes a patient to the occurrence of overwhelming post-splenectomy infection, laparoscopic partial splenectomy has been increasingly popular over the past two decades because it preserves the immune function of the spleen. This technique should only be performed by a well-trained team because of the high risk of bleeding. The authors report the cases of three patients who underwent laparoscopic partial splenectomy: a 7-year-old girl with no relevant history with a 4.5-cm epidermoid cyst involving the lower pole of the spleen, a 13-year-old boy, type 1 diabetic on insulin therapy, with a 7-cm epidermoid cyst of the upper pole of the spleen and a 14-year-old girl, with no previous history, with a 6-cm upper pole epidermoid splenic cyst. Operating times were 2 h 30 min, 3 h and 4 h 30 min, respectively. The intraoperative blood loss was 100 mL, 350 mL and 300 mL, respectively. The length of hospital stay was 6 days for each patient. No blood transfusion was performed perioperatively. With a mean follow-up duration of 21 months (32 months, 21 months and 10 months, respectively), no complication or recurrence occurred., (Copyright © 2024 Copyright: © 2024 African Journal of Paediatric Surgery.)

Abstract: Epidermoid cysts, also known as keratin cysts, are benign cystic malformations containing keratin and lipid-rich debris. These lesions generally present as painless, nontender, soft tissue masses. They can involve any part of the body but most commonly involve face, chest, back, and genital areas. They can have both congenital and acquired presentation. They are in general seen as a solitary skin nodule but can rarely present as multiple skin nodules. We present a case of a 52-year-old male patient who presented with multiple skin nodules involving face, chest, and back. After making a provisional diagnosis of an epidermoid cyst, surgical excision was performed. Histopathological examination confirmed the diagnosis of an epidermoid cyst. The patient's follow-up was uneventful, with no episodes of recurrence or infection. This report emphasizes the rarity of multiple widespread epidermoid cysts and the importance of considering differential diagnoses and appropriate intervention methods., (Copyright © 2023 Indian Journal of Pathology and Microbiology.)

An 82-year-old woman presented with a 6-month history of an enlarging brow mass that developed after trauma. Clinical and MRI appearance of the lesion appeared consistent with epidermal inclusion cyst. However, excisional biopsy demonstrated invasive squamous cell carcinoma, which recurred 6 weeks later and required repeat surgical excision. To our knowledge, this represents the first case of squamous cell carcinoma arising from a posttraumatic epidermal inclusion cyst., Competing Interests: The authors have no financial or conflicts of interest to disclose., (Copyright © 2024 The American Society of Ophthalmic Plastic and Reconstructive Surgery, Inc.)

Background: Lichen sclerosus (LS) is a chronic inflammatory disorder, presenting with pruritis and hypopigmentation of the vulvar and anogenital skin. LS presenting as a peri-clitoral mass has not been previously described., Case: A 5-year-old patient with vulvar pruritis and ultrasound showing a homogenous mass was referred for suspected clitoromegaly with normal labs. Examination demonstrated a prepubertal patient with a mobile, soft, peri-clitoral mass and surrounding hypopigmentation consistent with LS. The cyst was excised surgically; pathology revealed an epidermal inclusion cyst. Postoperatively, she began using topical steroids for LS with symptom resolution., Conclusion: Thorough workup of clitoromegaly negative for hormonal causes requires further investigation to determine an alternative etiology of the mass. We suspect that inflammatory changes of LS and pruritus resulted in the peri-clitoral inclusion cyst., Competing Interests: Conflicts of Interest The authors have no conflicts of interest to disclose., (Copyright © 2024. Published by Elsevier Inc.)

Objective: This study aims to examine the clinical characteristics and surgical management of pediatric testicular epidermoid cysts, thereby contributing to the existing body of knowledge pertinent to the diagnosis and therapeutic intervention s for this condition., Methods: A retrospective analysis was conducted on the clinical records of 23 pediatric patients diagnosed with testicular epidermoid cysts, who were admitted to our institution between April 2013 and February 2024. Concurrently, a comprehensive review and analysis of pertinent literature were undertaken to augment the findings., Results: The mean age at which the onset of epidermoid cysts was observed was 6.0 years. All cases were singular and unilateral. B-ultrasound diagnosis categorized 6 cases as epidermoid cysts, 11 as teratomas, and 6 as indeterminate, yielding a diagnostic sensitivity of 26.1%. All patients underwent testicle-sparing mass resection, and nine patients underwent rapid intraoperative frozen section analysis, revealing eight cases of testicular epidermoid cysts and one teratoma, with a diagnostic sensitivity of 88.89%. Postoperative histopathological examination confirmed the diagnosis of testicular epidermoid cyst., Conclusions: Pediatric testicular epidermoid cysts are an uncommon occurrence, primarily presenting as a painless scrotal mass, which can mimic the clinical features of malignant testicular tumors. Imaging modalities and histopathological assessment are pivotal in the diagnostic process for pediatric testicular epidermoid cysts. For cases where B-ultrasound is inconclusive, rapid intraoperative pathological examination should be considered., (© 2024. The Author(s), under exclusive licence to Springer-Verlag GmbH Germany, part of Springer Nature.)

Purpose: Epidermoid cysts (EC) and dermoid cysts (DC) typically appear as well-circumscribed lesions on CT. This study aimed to clarify the radiologic and histopathologic characteristics of orbital EC and DC and to determine the correlations between them., Methods: The medical records of 69 patients who underwent surgery for orbital DC or EC at Samsung Medical Center between January 2001 and August 2016 were retrospectively reviewed. The size and location of the cysts, rim enhancement, homogeneity of contents, presence of hemorrhagic or calcific components, radiodensity of contents, and extent of bony remodeling were evaluated using CT. Additionally, the cyst lining and contents were examined histopathologically., Results: Among patients with orbital cysts, EC and DC were diagnosed in 10 (14.5%) and 59 (85.5%) patients, respectively. Further, 50.0% of EC and 79.7% of DC were located in the superotemporal quadrant of the orbit. On orbital CT, the average radiodensity of EC and DC was 18.9 ± 56.2 and -67.9 ± 63.3 HU, respectively. The cystic contents were more frequently homogeneous than heterogeneous in both EC and DC; however, the radiodensity of cysts differed significantly, which may be attributed to sebaceous gland activity. Focal bony notching, bone remodeling under pressure, and bony changes from dumbbell-shaped cysts were observed more frequently in DC than in EC., Conclusions: Radiological and histopathological features are correlated in orbital EC and DC. Therefore, orbital EC and DC can be preoperatively differentiated using CT, based on the average radiodensity and bony remodeling., (Copyright © 2024 The American Society of Ophthalmic Plastic and Reconstructive Surgery, Inc.)

Benign tumors of the eye and eyelid are common in children and adults, and they rarely undergo malignant transformation. Their workup and management have evolved over the years with increasing advancements in surgical and laser therapies. This contribution focuses on describing the following benign eye and eyelid tumors and their diagnostic and treatment approaches: congenital and acquired melanocytic nevi; nevus of Ota (Hori nevus); conjunctival papilloma; seborrheic keratosis; epidermoid cyst; dermoid cyst; milium; xanthelasma; hemangioma (cherry angioma and pyogenic granuloma); neurofibroma; neurilemmoma (schwannoma); and fibroepithelial polyp. Surgical removal is the primary treatment approach for many of these benign tumors. With advancements in laser technologies, there are now several laser types that can be used in the treatment of these benign eye and eyelid tumors. Other treatment modalities include cryosurgery, electrosurgery, and topical or intralesional medications. We hope this review will provide a reference to dermatologists and ophthalmologists in their approach to evaluation and management of benign eye and eyelid tumors., Competing Interests: Declaration of competing interest The authors declare no conflicts of interest., (Copyright © 2024. Published by Elsevier Inc.)

Competing Interests: Les auteurs déclarent n’avoir aucun lien d’intérêts.

Lymphoepithelial cyst(LEC)of the pancreas is a relatively rare benign cystic disease of the pancreas. In this report, we describe a case of LEC in which a malignant tumor could not be ruled out by preoperative diagnosis and surgery was performed. The patient was a 72-year-old man. A simple CT scan of the chest and abdomen performed as a follow-up for another disease incidentally revealed a mass in the pancreatic tail. Enhanced CT of the abdomen showed a tumor approximately 3 cm in size at the pancreatic tail with no contrast effect. MRCP showed moderate signal on T2WI, high signal on T1WI, and high signal on T2WI on some cysts inside the pancreas. PET-CT showed slight uptake of FDG. Both tumor markers CEA and CA19-9 were normal. Therefore, malignant disease such as pancreatic IPMC could not be ruled out, and laparoscopic distal pancreatectomy plus splenectomy was performed. The pathology results showed a diagnosis of pancreatic lymphoepithelial cyst with slight differentiation into sebaceous gland.

Cutaneous cystic lesions (n = 35) were examined with optical coherence tomography. Cysts were visible as a hyporeflective roundish area with a clear margin; in some cases, the epidermis was thinned. Epidermal cysts, trichilemmal cysts, and hidrocystomas had a linear margin representing the epithelium of the cyst, whereas mucoid pseudocysts showed no linear margin. Trichilemmal and epidermal cysts presented with hyperreflective content that corresponds to keratin. By visualizing the margin and the content of the cyst, it was possible to differentiate between different types of cysts., (© 2023. The Author(s).)

Competing Interests: Conflicts of interest The authors declare no conflicts of interest.

Rationale: Epidermoid cyst (EC) is a common clinical condition and it can be filled with keratinized material. EC often represents painless, slow progressive growth, and single cyst. The cyst is usually 1 to 5 cm in size. Giant epidermoid cysts on the buttock area are extremely rare, and reports of giant epidermoid double cysts on the buttock are even rarer., Patient Concerns: This paper reports a patient with a painless mass was on the left buttock., Diagnosis: A giant epidermoid double cysts with infection in a left buttock paranal location., Interventions: The mass was surgically removed., Outcomes: The patient recovered well after surgical treatment and currently has no recurrence., Conclusion: For patients with EC, MRI is recommended as a routine examination before surgery in order to detect the variation and extent of the cyst early. This lays a foundation for the complete resection of the lesion during the operation. The review of relevant literature will hopefully be helpful to clinicians., Competing Interests: The authors have no conflicts of interest to disclose., (Copyright © 2024 the Author(s). Published by Wolters Kluwer Health, Inc.)

Epidermoid bone cysts are rare, unilocular, and slow growing. They develop by the accumulation of ectodermal remnants, and they may be congenital or acquired. The most common locations for these bone cysts are the distal phalanges, followed by the skull. This paper documents an adult male from the Islamic (twelfth and thirteen centuries CE) burial site of Ibi in the Province of Alicante, southeast Spain. This individual had a cranial lesion in the form of a roughly elliptical hole in the posterior fossa (left occipital region). The lesion was examined macroscopically and using X-ray photography. Based on the shape of the lesion, the most likely diagnosis would appear to be a benign tumour, a so-called "hourglass" epidermoid cyst. No direct link between this tumour and the cause of death can be established.

BACKGROUND Splenic cysts are classified as either parasitic or non-parasitic cysts, with both types sharing similarities in their clinical presentation and imaging findings. Most splenic cysts are of parasitic origin, while non-parasitic splenic cysts are less common. Splenic epidermoid cysts (SECs) are a rare subtype of non-parasitic cysts and compromise only around 10% of them. CASE REPORT In this paper we present a case of 22-year-old man with no significant past clinical history, who presented with non-specific, vague symptoms, including persistent left upper-quadrant pain and discomfort for the last 2 years. A physical examination and extensive laboratory tests were inconclusive. Subsequently, the patient underwent multiple imaging studies including ultrasonography and computed tomography (CT) scan of the abdomen. His ultrasonographic findings were consistent with the diagnosis of hydatid cyst, which was further emphasized by its frequent occurrence in clinical practice, as our country is considered an endemic region. In light of this, he underwent laparoscopic splenectomy following percutaneous cyst drainage. The consequent histopathological examination revealed the diagnosis of splenic epidermoid cysts. CONCLUSIONS When encountering splenic cysts in regions where parasitic infections are endemic, special attention is needed, as physical examination, laboratory tests, and imaging studies alone are insufficient to differentiate among the types of cysts. Histopathological examination remains the diagnostic tool of choice, particularly when imaging findings are inconclusive. Splenectomy, with either a laparoscopic or open approach, is the treatment of choice for splenic cysts to prevent recurrence as well as other potential catastrophic complications.

FLOTCH (leukonychia totalis-trichilemmal cysts-ciliary dystrophy syndrome) syndrome is a rare genetic cutaneous disorder primarily characterized by multiple recurrent trichilemmal pilar cysts and leukonychia. It may be associated with ciliary dystrophy, koilonychia, and/or less frequently renal calculi and pancreatitis inherited in an autosomal-dominant fashion. We report the case of a 25-year-old Black woman who presented with white-colored fingernails and enlarging cysts in multiple locations including the scalp, rib cage, and forearm and was diagnosed with suspected FLOTCH syndrome. Pilar cysts in unusual locations along with distinct nail changes should prompt clinicians to consider further investigation for conditions such as FLOTCH syndrome.

Epidermoid cysts are generally benign neoplastic lesions, the etiology of which is unclear and is mainly related to epithelial cells left in the tissues during the embryonic period and traumatically implanted in the tissues. The most common intraosseous sites are the phalanges and the skull. Epidermoid cysts occurring in the jaws are clinically rare. In this paper, we report a case of epidermoid cyst occurring in the mandible with embedded teeth and discuss the etiology, clinical manifestations, diagnosis, and treatment of epidermoid cysts in the jaws in the context of the relevant literature.

Rationale: Trichilemmal cyst (TC), also known as trichodermal cyst, trichodermal isthmus-degenerative cyst. It is a benign skin lesion originating from the outer hair root sheath, with low incidence and few reports., Patient Concerns: A 41-year-old patient had found a scalp lump for more than 10 years. A 2.0 cm × 1.0 cm × 1.0 cm lump on the right occipital region was touched more than 10 years ago without special treatment. In the past 2 years, the lump has gradually increased. Physical examination: 4 protruding lumps can be reached in the scalp. One lump in the right occipital region is about 3.0 cm × 2.0 cm × 2.0 cm, with 1 lump immediately below and 2 lumps in the left temporal region. All lumps can be pushed., Diagnoses: The lesion is located in dermis, The lesion is solid, and the contents of the cyst were cheese-like white material, and the inner and outer walls of the cyst were smooth and shiny. Pathological results showed that the lesion was TC. The cyst wall is epidermal tissue, the spinous layer and basal layer are intact, there is no granular layer, and the protein in the cyst is dense., Interventions: All lumps were completely surgically removed., Outcomes: The wound healed well after TC resection. There was no recurrence of TC after 1 year follow-up., Lessons: The clinical manifestations of scalp TC are not specific, and the diagnosis needs pathological examination, and the prognosis of total excision is good., Competing Interests: The authors have no funding and conflicts of interest to disclose., (Copyright © 2023 the Author(s). Published by Wolters Kluwer Health, Inc.)

Introduction: Trichilemmal cysts (TCs) are common benign cysts that form from the hair follicles in the skin. Proliferating trichilemmal cysts (PTCs) are rare types of TCs characterized by rapid cellular proliferation. Malignant transformation of PTC (MPTC) is a rare adnexal tumor that account for <0.1% of all skin cancers. TCs and PTCs are benign tumors; however, MPTCs grow rapidly and are prone to metastasis., Case Presentation: A 77-year-old man was referred to our hospital with a solitary pinkish mass on his left elbow. Trichilemmal carcinoma arising from a PTC was confirmed through excisional biopsy, and wide excision was performed. One month postoperatively, a cystic mass was observed and was suspected to have local recurrence; however, bursitis was confirmed after excisional biopsy. After 1 year of follow-up, the patient maintained an improvement without recurrence or any other surgical complications., Conclusions: In addition to being a very rare disease, MTPC occurred in the elbow of a man who does not fit the general etiology; therefore, it is considered an interesting case, and we report this case for academic contribution., Competing Interests: The authors have no funding and conflicts of interest to disclose., (Copyright © 2023 the Author(s). Published by Wolters Kluwer Health, Inc.)

Keratinous cysts are amongst the 10 most common dermatologic ambulatory diagnoses. Thus, we aimed to estimate the time and cost spent annually on management of keratinous cysts. We conducted a cross-sectional study using the National Ambulatory Medical Care Survey and the National Hospital Ambulatory Medical Care Survey between 2007 and 2018 (most recent years available). Conservatively, $2.1 billion per year was spent on healthcare for keratinous cysts. On average, the full-time work of 1200 (840-1800) physicians and non-physician providers are required to manage keratinous cysts yearly in the outpatient and emergency departments.We used Medicare reimbursement rates for the cost analysis which provides a conservative estimate of the total cost. Keratinous cysts impose a significant time and cost burden on the healthcare system. Treating inflamed, draining, or painful keratinous cysts or ones that occur in undesirable locations such as the face are likely of high-value due to the quality of life impact. Managing asymptomatic keratinous cysts may be of lower value. Given this burden, clinicians should continue to evaluate the value they are providing to the patient when managing keratinous cysts.

BACKGROUND Lowe syndrome, also known as oculocerebrorenal syndrome, is a rare genetic condition caused by an X-linked mutation of the OCRL1 gene, with an estimated prevalence in the general population of approximately 1 in 500 000. It is a multisystem disorder most commonly affecting the eyes, central nervous system, and kidneys. These commonly manifest as congenital cataracts, intellectual disability, and proximal renal dysfunction (Fanconi-type). Epidermal lesions are an uncommon manifestation of this condition, and the association is not completely understood. CASE REPORT Here we present a case of a 9-year-old boy with Lowe syndrome who presented with multiple cystic masses found in the perianal region. An excision was then performed to remove the masses and found that the lesions were epidermal cysts, which are infrequently found in Lowe syndrome. After excision, the patient recovered uneventfully without complications. CONCLUSIONS While epidermal cysts are an uncommon manifestation that have been documented, our case remains unique given the location and associated symptoms of the lesions. At presentation, the constellation of pain and perianal masses was concerning for a malignant etiology. However, after diagnostic imaging was performed, these lesions were found to be epidermal cysts, an infrequent manifestation of Lowe syndrome. Few previous case reports described cystic lesions in association with Lowe syndrome, and none, to our knowledge, have described multiple symptomatic perianal lesions. This case is important to consider because epidermal cystic lesions can be found with this presentation and should be considered on differential diagnoses for dermatologic findings in Lowe syndrome patients.

Splenic epithelial cysts are rare in humans and have not been reported in animals, to our knowledge. During a routine medical examination of a 12-y-old castrated male Maltese dog, a splenic mass was found and subsequently removed via splenectomy. Histologically, a well-defined multilocular cyst in the spleen was lined mostly by simple cuboidal, multifocally by stratified cuboidal, or occasionally by stratified squamous epithelium. Immunohistochemically, the lining cells were positive for cytokeratin and negative for vimentin, CD31, and Wilms tumor protein 1. The case was diagnosed as a primary splenic epidermoid cyst.

Background: To construct a prediction model based on the clinical characteristics of epidermoid cysts to identify pathologic infections, evaluate the diagnostic accuracy of the model, and conduct preliminary verification. Patients and Methods: We conducted a retrospective analysis of 314 patients diagnosed with epidermoid cysts that had been removed surgically. The clinical and pathologic data of all patients were collected. The patients were divided randomly into modeling group and verification group in a 75:25 ratio. In the modeling group, the multifactor logistic regression method was used to construct a prediction model for identifying epidermoid cyst pathologic infection, and the receiver operating characteristic (ROC) curve was used to evaluate the diagnostic accuracy of the model, which was then validated in the verification group. Results: All 314 patients with epidermoid cysts were divided into non-infected group (183 cases) and infected group (131 cases) according to the pathologic results. Logistic regression analysis showed that the disease course, growth trend, redness, and texture of epidermoid cysts were independent factors affecting pathologic infection. The above four indicators were selected to construct the prediction model of epidermoid cyst pathologic infection. In the modeling group, the prediction model showed an area under the curve (AUC) of 0.898, with the sensitivity of 0.830, specificity of 0.890, positive likelihood ratio of 7.523, and negative likelihood ratio of 0.191. The AUC of the prediction model in the verification group was 0.919, which was not significantly different from that of the modeling group (p = 0.886). Conclusions: The prediction model based on the clinical characteristics of epidermoid cysts had good diagnostic accuracy and high specificity; it can be used to identify pathologic infections of epidermoid cysts.

Introduction: when faced with a chronic digital injury, the differential diagnosis between osteomyelitis or primary tumor is raised. Coexistence between osteomyelitis and epidermoid bone cyst is not uncommon., Material and Methods: in this article, we describe two cases of epidermoid cysts in distal phalanx of the hand associated with osteomyelitis and a review of the literature is presented., Results: both osteomyelitis and epidermoid bone cyst have been related to the presence of previous trauma at the site of the lesion, nail alterations and chronic phlogotic signs, so it is important to reach a diagnosis of certainty through an anatomopathological study and to perform a good surgical debridement to ensure the healing of both entities., Conclusions: surgical debridement associated with curettage and filling of the bone defect with bone substitute with antibiotic is a good therapeutic option in the treatment of these lesions.

Rationale: Uro-originated epidermoid cysts, especially located in the upper urinary tract are rare and only 4 cases of epidermoid cyst occurring in the upper urinary tract have been reported worldwide so far. In the previous cases, the cysts were diagnosed as tumors and organs were removed., Patient Concerns and Diagnosis: We report a case of epidermoid cyst in ureter in a 48-year-old female patient admitted to the local hospital suffering from paroxysmal pain in the right hypochondriac for 8 years., Interventions and Outcomes: She underwent right ureteroscopy in order to rule out the possibility of urinary epithelial carcinoma. The tumor was pathological diagnosed as a benign ureterocyst epidermoid. Postoperatively, the patient showed good recovery. During the 24-month follow-up period, the patient remained well and free of complications., Conclusion: This case illustrates that benign epidermoid cysts can appear in the ureter, although it is extremely rare. It also indicates that perioperative examinations must be exhaustive to avoid the further injury to the patients., Competing Interests: The authors have no conflicts of interest to disclose., (Copyright © 2022 the Author(s). Published by Wolters Kluwer Health, Inc.)

In this paper, we report the case of a 71-year-old man with an 8-year history of melanonychia on the right little finger, who referred to our hospital because the color of pigmented area had gradually darkened and the width had expanded. Physical examination revealed longitudinal melanonychia with brown color (4 mm in width). Dermoscopic examination revealed multiple white round clods and splinter hemorrhages. No micro-Hutchinson sign was observed. We performed a punch biopsy (diameter 3 mm) of the nail matrix for diagnosis. Histopathological examination revealed irregular acanthosis of epithelium of the nail bed and distal matrix, which consisted of basaloid cells without nuclear atypia. Several zones exhibited cell whorls reminiscent of squamous eddies. The whorls were composed of large pink cells arranged in an onion peel-like fashion. The basaloid cells tested negative for human papillomavirus in situ hybridization and p16 staining. The morphology of white round clods (milia-like cysts in metaphoric term) observed in dermoscopic analysis corresponded to squamous eddies in histopathology. Considering these features, ungual seborrheic keratosis (SK) with longitudinal melanonychia was diagnosed, which is an atypical site for SK. We suggest that the dermoscopic finding of milia-like cysts may be useful for the diagnosis of ungual SK., (© 2022 Japanese Dermatological Association.)

Purpose: The purpose of this study was to characterize intradiploic dermoid and epidermoid orbital cysts to determine any differences in clinical, radiographic, or surgical features., Methods: A retrospective review was performed of patients presenting with intradiplopic dermoid or epidermoid cysts. Additionally, a complete review of the literature was performed to identify cases of intradiplopic orbital dermoid and epidermoid cysts. Data collected included age, sex, presenting symptoms, location of intradiplopic cyst, ophthalmic findings, treatment, and follow-up. Clinical features of dermoid versus epidermoid cyst were compared. Additionally, machine-learning algorithms were developed to predict histopathology based on clinical features., Results: There were 55 cases of orbital intradiploic cysts, 49 from literature review and six from our cohort. Approximately 31% had dermoid and 69% had epidermoid histopathology. Average age of patients with dermoid cysts was significantly lesser than that of patients with epidermoid cysts (23 vs. 35 years, respectively; P = 0.048). There was no difference between sex predilection, presenting symptoms, radiographic findings, or surgical treatment of dermoids and epidermoids. The majority of patients (64%) underwent craniotomy for surgical removal. Machine-learning algorithms KStar and Neural Network were able to distinguish dermoid from epidermoid with accuracies of 76.3% and 69%, respectively., Conclusion: Orbital intradiploic cysts are more commonly epidermoid in origin. Dermoid cysts presented in younger patients; however, there were no other significant differences in features including ophthalmic or radiographic findings. Despite similar features, machine learning was able to identify dermoid versus epidermoid with good accuracy. Future studies may examine the role of machine learning for clinical guidance as well as new surgical options for intervention., Competing Interests: None

Background: Cysts of the skin are observed frequently and their diagnoses are generally straightforward. However, atypical cystic lesions for which differentiation is indistinct have been noted., Methods: We examined five cases of trichilemmal cyst with proteinaceous material (TCPM), which required differentiation from sweat duct/gland tumors. We investigated the histopathological findings of TCPMs and evaluated the immunohistochemical expression of cytokeratin (CK) 10, CK13, CK17, CK19, CD8, and CD117. Immunohistochemical analysis was performed on the 5 TCPMs, 10 trichilemmal cysts (TCs), 5 clear-cell hidradenomas, 5 poroid hidradenomas, and cutaneous normal adnexa., Results: Apoptotic cells were present in the cyst wall with a small amount of keratin or calcification in the cavity of TCPMs. The TCPMs and TCs were negative for CK19 and CD117, on the other hand clear-cell hidradenoma and poroid hidradenoma were positive for CK19 and CD117. The restricted positivity for CK10 was detected in the suprabasal layers of the cyst walls of TCPMs and TCs. The immunostaining patterns of TCPMs and TCs were similar to those of normal follicular isthmus., Conclusions: The histopathological findings with characteristics of TCs and a panel of immunohistochemical antibodies including CD117, CK19, and CK10 contributed to a correct diagnosis of TCPM., (© 2022 John Wiley & Sons A/S. Published by John Wiley & Sons Ltd.)

Background: Palpable masses of the head and neck are a common indication for imaging in the pediatric population. Midline lesions of the infrahyoid neck, particularly lesions isolated to the suprasternal notch, are not well studied., Objective: To delineate the histopathological and imaging spectrum of masses that occur within and isolated to the suprasternal notch., Materials and Methods: A retrospective study was performed to identify patients with an isolated lesion of the suprasternal notch that had available pathological diagnoses. Available imaging was reviewed and characterized by fellowship-trained pediatric radiologists and compared by descriptive statistics to the final pathological diagnoses., Results: Eighteen masses isolated to the suprasternal notch with available pathological diagnoses were identified. Of these, congenital epithelial inclusion cysts were diagnosed in 14 patients (77.8%) with dermoid cysts comprising 11 of those (61.1%) and epidermoid cysts accounting for 3 (16.7%). The most common imaging appearance was a cystic or pseudosolid appearance without vascularity., Conclusions: Isolated resected lesions of the suprasternal notch in pediatric patients are most frequently dermoid/epidermoid cysts, with a differential diagnosis including other less common entities., (© 2022. The Author(s), under exclusive licence to Springer-Verlag GmbH Germany, part of Springer Nature.)