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Folliculosebaceous Cystic Hamartoma (FSCH) is an uncommon cutaneous hamartomatous lesion. It is basically a tumour like malformations exhibiting abnormal overgrowth of biphasic elements i.e., epithelial and mesenchymal components that are normally found in the skin. Few other hamartomas of pilosebaceous origin are trichofolliculoma, trichodiscoma, fibrofolliculoma and pilar sheath acanthoma. Though distinct, this entity shares similar histological features to Sebaceous Trichofolliculoma (STF). Hence, a proper histological examination is must in differentiating it from STF and other clinical and histological entities. Authors hereby, describes a case of FSCH in a 37-year-old male who presented with a slow growing cystic mass on his left earlobe, an uncommon location for such lesion. The mass was excised, and a detailed histological evaluation showed a characteristic multinodular growth pattern with lobules of pilosebaceous glands forming nodules around cystically dilated follicular infundibular structures. No hair shafts were seen in the cystic cavity ruling out differential diagnosis of sebaceous hyperplasia which could have been a close mimic. The intervening stroma revealed dense collagen, sheets and lobules of adipocytes, many vascular channels filled with fibrinous deposits. Perivascular adipocytes were also noted along with few nerve tissues (perineurium). A detailed clinicopathological work-up helped in arriving at a final diagnosis of FSCH with neural component. The patient was doing well till last six months of follow-up. No recurrence of similar lesion was noted in the patient.

Intraoral cutaneous hamartomas (ICHs) are uncommon mucosal lesions characterized microscopically by a combination of cutaneous structures, including various stages of follicular and sebaceous elements. Due to their rarity, the clinicopathologic and immunohistochemical attributes of ICHs have not been thoroughly delineated. Three cases of ICH were identified from our records, and formalin-fixed paraffin-embedded sections were immunohistochemically stained with antibodies against androgen receptor, estrogen receptor, and progesterone receptor, p63, factor XIIIα, and CD34. All 3 ICHs involved the buccal mucosa with an M:F ratio = 2:1 and mean age = 42.3 years (age range: 27-61 years). ICHs presented as thickened, painless, white and yellow plaques or nodules of long duration, measuring 0.6-1.5 cm. No history of skin graft in the area of the lesions was reported. Histopathologically, the lesions showed aggregates of rudimentary folliculosebaceous structures. Although well-defined piloerector muscles were present in all cases of ICH, bona fide hair follicles and isolated hair shafts were identified only in 1 case. The overlying oral epithelium exhibited epidermis-like morphological features, while inflammation was generally absent. Immunohistochemically, strong and diffuse nuclear staining for androgen receptor and factor XIIIα was observed in the sebaceous glands, and estrogen receptor and p63 reactivity were confined exclusively to the peripheral basal cells, while progesterone receptor staining was negative in ICHs. CD34 diffusely decorated the lesional stroma. In conclusion, ICH is a rare lesion composed of cutaneous elements in an abnormal location. A predilection for the buccal mucosa is reported in the current study.

Sebaceous glands are sebum-secreting components of pilosebaceous units. The embryological development of the sebaceous gland follows that of the hair follicle and epidermal tissue, beginning between weeks 13 and 16 of fetal development. New sebaceous glands do not normally develop following birth, but their size increases with age. Sebocytes express a multitude of hormone receptors and are heavily regulated to secrete sebum by androgens. There is a large increase of sebum excretion at birth and again at puberty, until approximately age 17. In adulthood, sebum production remains stable and declines to zero in postmenopausal women and in men aged 60-70. Besides the production and release of sebum, sebaceous glands function to lubricate the skin and hair, provide thermoregulation, and exhibit antimicrobial activity. Research has shown sebaceous glands to possess the cellular capability to transcribe genes necessary for androgen metabolism. Dysfunction of the sebaceous gland can be seen primarily in steatocystoma simplex and multiplex, sebaceous gland hyperplasia, sebaceoma, sebaceous adenoma, sebaceous carcinoma, nevus sebaceus, and folliculosebaceous cystic hamartoma. Sebaceous glands are secondarily involved in acne vulgaris, seborrheic dermatitis, and androgenic alopecia. This article is protected by copyright. All rights reserved.

Background/objective The pathogenesis of infantile hemangiomas (IH), PHACE, and LUMBAR syndromes remains unknown. We aim to describe histopathologic features of midline anomalies associated with IH, including patients with PHACE and LUMBAR syndromes. Methods A multicenter retrospective chart review was performed to identify patients with IH, PHACE, and LUMBAR syndrome with histopathologic specimens from sternal or midline anomalies. A total of 18 midline lesions from 13 patients were included. Out of 18, 14 midline lesions underwent both histopathologic and clinical review. Three hamartoma-like chin plaques and one supraumbilical raphe underwent only clinical review. Results All 13 patients had midline lesions and IH. Histopathologic diagnoses were as follows: rhabdomyomatous mesenchymal hamartoma (3), folliculosebaceous cystic hamartoma (1), fibroepithelial polyp (1), verrucous epidermal hyperplasia with vascular proliferation and fibroplasia (1), congenital midline cervical cleft (1), pericardium with fibrosis (1), fibrous components with increased collagen (1), atrophic skin/membrane (3), angiolipomatous mass with neural components (1), and lipomatous mass (1). Due to the retrospective nature of this study, it was not possible to obtain pathology slides for all midline lesions that had previously been biopsied or resected. We show clinically and histopathologically a new association between PHACE syndrome and rhabdomyomatous mesenchymal hamartoma (RMH), in addition to demonstrating the association between PHACE syndrome and chin hamartomas. We also display histopathologic findings seen in midline lesions resected from LUMBAR patients. Conclusion Rhabdomyomatous mesenchymal hamartoma is thought to be related to aberrations of mesenchymal cells during development; therefore, this may provide clues to the pathogenesis of IH and related syndromes.

We report a case of a slowly growing papule on the nasal bridge of an elderly woman. Histopathological findings revealed a very unusual type of folliculosebaceous cystic hamartoma with a retiform and primitive epithelial proliferation associated with the stromal component. Folliculosebaceous cystic hamartoma is an uncommon lesion that involves a cystically dilated follicle embedded in a stroma of distinct mesenchymal tissue. Because folliculosebaceous cystic hamartoma is a rare and clinically indistinct lesion, clinical photographs of the lesion are not widely available. A recent search on PubMed revealed less than 50 published articles on folliculosebaceous cystic hamartoma; among these manuscripts there was a scarcity of clinical images of the lesion. This disparity is to be expected as the lesion typically has a very indistinct presentation. We thus describe an inconspicuously appearing case of folliculosebaceous cystic hamartoma to bring attention to the indistinct clinical morphology of the lesion and to report a histopathologically uncommon variant.

Background Cysts are very common in the routine of dermatopathology but follicular germinative (trichoblastic) differentiation in cysts is seen rarely. The presence of follicular germinative differentiation in a cyst alerts to consider the possibility of a basal cell carcinoma (BCC) arising in a cyst. Methods Five cystic lesions with zones of follicular germinative differentiation were collected. Hematoxylin and eosin sections were reassessed for architecture, types of follicular differentiation and stromal characteristics; immunohistochemical studies with Ber-EP4 were analyzed. Articles about follicular germinative differentiation in cystic lesions were reviewed. Results Cystic lesions with follicular germinative differentiation have been described in the literature under various names including trichoblastic infundibular cyst, cystic trichoblastoma, cystic panfolliculoma (CPF), dermoid cyst with basaloid proliferations, folliculosebaceous cystic hamartoma and BCC occurring in infundibular cysts. The lesions presented by us could be classified as three cystic trichoblastomas, one CPF and one cystic hamartoma with follicular germinative differentiation. Conclusions Histopathologically, cystic trichoblastomas can be separated from CPFs. Some lesions defy classification and may be regarded as cystic follicular hamartomas. The presence of follicular papillae and bulb-like structures, advanced follicular differentiation like that of inner and outer root sheath exclude the differential diagnosis of BCC arising in a cyst.

Objective Folliculosebaceous cystic hamartoma (FSCH) represents an unusual type of cutaneous hamartomatous proliferation, manifesting clinically as an asymptomatic, slow-growing papulo-nodular lesion that most commonly affects the facial skin, primarily around the nose. Microscopically, FSCH is composed of infundibular structures with numerous radiating sebaceous lobules embedded in a mesenchymal stromal component. Despite the nomenclature, significant cystic dilatation is observed in Results Three FSCH cases were identified in the archives of the Oral and Maxillofacial Pathology Laboratory, University of Minnesota between 2008-2017 with M:F ratio=2:1 and mean age =42.3 years (age range: 27-61 years). All cases were located in the buccal mucosa and presented as painless, submucosal nodules of long duration measuring 0.6-1.5 cm. No previous history of skin graft in the area of the lesions was reported and none of the patients had a clinically identifiable syndrome. Histopathologically, oral FSCHs showed aggregates of variable number of rudimentary follicular structures and sebaceous lobules. Occasionally, the sebaceous glands were radially arranged and attached to small in size infundibular structures featuring rare microcystic changes, or were scattered in the deeper portions of the oral mucosa. The pilosebaceous units were immersed in a dense, focally desmoplastic, connective tissue stroma with variable amounts of mature adipocytes and vessels. Piloerector muscles were present in 2 out of 3 FSCHs, while inflammation was generally absent. Conclusions Oral FSCH is an infrequent lesion which can be misdiagnosed as ectopic Fordyce granules or other sebaceous neoplasms. Similar to a subgroup of cutaneous FSCH, oral lesions fail to show prominent cystic formation. Notably, a predilection for the buccal mucosa is reported. Whether oral FSCH represents late developing stage of trichofolliculoma remains unknown.

Folliculosebaceous cystic hamartoma is a distinctive cutaneous hamartoma composed of follicular, sebaceous, and mesenchymal components. The lesions are most commonly found on the face and scalp of young adults, with approximately 30% occurring in the nasal or paranasal regions of the face. The clinical differential diagnoses are extensive and include epidermoid cyst, dermal nevus, soft fibroma, and adnexal tumors including sebaceous neoplasms. Here, the authors present a case of a 24-year-old man who presented for evaluation of an asymptomatic growth on the nose, which had slowly enlarged over 9 years. On examination, there was a 0.6 cm dome-shaped flesh-colored papule on the nasal bridge. The clinical differential included dermatofibroma versus intradermal nevus. A shave biopsy was performed, and histological examination of the sections showed a proliferation of multiple enlarged and irregular-appearing sebaceous glands attached to a cystic follicular structure. The associated dermal mesenchymal component consisted of numerous mature-appearing adipocytes associated with a fibromyxoid stroma, prominent collections of mucin, and bundles of ropey collagen resembling a spindle cell lipoma. This combination of a folliculosebaceous cystic hamartoma with a spindle cell lipoma-like mesenchymal proliferation is unusual and has not been previously reported.

Some authors have reported that the secondary hair follicles in trichofolliculomas (TF) undergo regressive changes and are subsequently replaced by the developed sebaceous elements, and that folliculosebaceous cystic hamartoma (FSCH) is a TF at a very late stage. In the present study, we revaluated the histopathological features of 40 TF lesions, focusing on their chronological changes. The results of the present study indicate that while the secondary follicles in the TF exhibited the hair cycle, the normal hair cycle was out of control, and tertiary hair follicles randomly developed from the involuting secondary follicles. The repeated development of hair follicles in this disordered hair cycle caused the development of chains of several continuous hair follicles in late-stage TF. In the TF lesions, no features indicating the replacement of the regressing secondary hair follicles by any sebaceous elements were observed, thereby suggesting that FSCH is not a very-late-stage TF.

The histogenesis of folliculosebaceous cystic hamartoma (FSCH), including the origin of the frequently associated adipocytes and other mesenchymal components, remains unclear. There are controversial problems regarding FSCH, such as the relationship between FSCH and trichofolliculoma (TF), and the exact concept of sebaceous TF. Fourteen FSCHs and 1 sebaceous TF were revaluated for the histopathology and studied for immunohistochemical profile of various cytokeratins, hair follicular stem cell markers, and others. The nestin expression was partly upregulated in the sebaceous duct structures and the proliferating spindle cells in the surrounding connective tissue in some lesions. S-100 protein staining clarified the presence of lipogenesis in these nestin-expressed lesions, and the nestin-positive spindle cells were also seen around the immature adipocytes. Some FSCHs showed the focal follicular differentiation, where no signs of catagen or telogen stage were seen. One peculiar case showed both FSCH and TF features equally. The possibility that the adipocytes and other mesenchymal components in FSCHs originated from the nestin-positive multipotent stem cells was suggested. It is not convincing that FSCH and TF represent a chronological change in the spectrum of the same condition. Each FSCH and TF is therefore considered to be a distinctive entity. They may develop under a similar pathogenesis differing from each other in the direction of fundamental differentiation. In contrast to the TF lesions, the unusual upregulation of nestin expression is occasionally seen in FSCH lesions, including their stromas, which may thus result in the production of various kinds of mesenchymal components in FSCHs.

Folliculosebaceous cystic hamartoma (FCH) is a relatively rare and recently described lesion of the skin. Mostly, it involves the skin of the head and neck area. It is considered by most authors as a form of non-neoplastic cutaneous hamartoma comprising follicular, sebaceous and stromal elements. However, few regard it as a sebaceous trichofolliculoma, i.e. a variant of trichofolliculoma. FCH of the nipple of female breast is a very rare lesion with only one previous case reported so far in the literature. We report a similar case with a brief review of the literature.

Background Folliculo-sebaceous cystic hamartoma (FSCH) is an uncommon skin condition presenting as a slow-growing papulo-nodular lesion, in or around the nose. Most cases are not clinically suspected and only histopathological examination allows the diagnosis. Pathological features include a dermal-located infundibulo-cystic structure with sebaceous glands radiating around, a stromal component encircling the epithelial structures, with clefts between the lesional epithelial and stromal parts, as well as between this and the adjacent dermis. Results We report eight patients with the diagnosis of FSCH (5 females and 3 males), with ages ranging from 35 to 77 years. Most cases (5 out of 8) were located in or around the nose and sizes were comprised between 0.6 and 1.2 cm. Lesions had grown for long periods of time, up to ten years in one case. Immunohistochemistry showed staining for p63 in the epithelial component of all lesions, while CD10 was only present in some sebocytes. CD34 and Factor XIIIa positive cells were present in the lesional stroma. Staining for androgen and alpha-estrogen receptors was also usually noticed. Conclusions FCSH is a hamartomatous skin lesion, clinically indistinct but with well-defined histopathological features. Immunohistochemistry shows a profile very close to normal sebaceous glands. © 2008 Blackwell Munksgaard.

Folliculosebaceous cystic hamartoma (FSCH) is a rare cutaneous hamartoma consisting of dilated folliculosebaceous units invested in mesenchymal elements. These solitary lesions typically affect adults, have a predilection for the central face or scalp, and remain less than 1.5 cm in greatest dimension. Although giant FSCH variants have been documented, the congenital presentation of a giant FSCH stands in contrast to earlier views of its histogenetic relationship with trichofolliculoma. We describe a giant pedunculated FSCH arising from the posterior neck of a 9-month-old Hispanic male and discuss various aspects of this highly unusual case.

Folliculosebaceous cystic hamartoma (FSCH) is a distinct type of cutaneous hamartoma of pilosebaceous origin that usually occurs on the face. For FSCH, other parts have been reported such as the genital area, and the trunk. A 50-year-old woman presented with an asymptomatic dome-shaped scalp nodule. The clinical diagnosis was pilar cyst or tumor. Histopathological assessment showed FSCH with absolute neural component as the only mesenchymal stroma, leading to the diagnosis of folliculosebaceous cystic neural hamartoma. To the best of our knowledge, absolute neural stroma in FSCH has not been reported previously in the literature.

Background: Folliculosebaceous cystic hamartoma (FSCH) is a rare cutaneous hamartoma consisting of dilated folliculosebaceous units invested in mesenchymal elements. These lesions have a striking predilection for the central face and scalp of adults. The vast majority of lesions present as 0.5–1.5-cm papules or exophytic nodules. A single case of giant FSCH has been reported on the upper back. Methods: A 32-year-old woman presented with a (15 cm in greatest dimension) plaque-like, multinodular lesion on her left upper arm for several years. The lesion was clinically suspected to be a nevus sebaceus. Results: The skin excision showed numerous dermal and subcutaneous dilated follicular structures with peripherally radiating sebaceous lobules, hair follicles, and surrounding mesenchymal elements consistent with FSCH. Conclusion: To our knowledge, this is the second case of giant FSCH. Our case is unique for its larger size, more plaque-like growth, and location on an extremity when compared to the seminal case of giant FSCH.

Folliculosebaceous cystic hamartoma (FSCH) is a cutaneous hamartoma of pilosebaceous origin that usually occurs on the face. We present what we believe is only the second reported case of FSCH of the external auditory canal, and the first in an adult. The patient was a 59-year-old woman who presented with a 4-year history of a firm nodule on the left external auditory canal that had caused hearing loss, pruritus, and pain. The lesion was excised, and histopathologic examination identified infundibular cysts, hyperplasia of the sebaceous lobules, and a large amount of mucin, features that are consistent with FSCH. One year postoperatively, the patient was asymptomatic, and no evidence of recurrence was noted.

Trichofolliculoma (TF) is a hamartomatous hair follicle-related tumor, clinically described as a dome-shaped papule with a central pore crossed by one or more silky white hairs. Histologically, it described as a cystic cavity containing keratinous debris, hair shaft fragments, and numerous hair follicles arising from its linings. Collision or compound tumors are a coexistence of two or more identifiable tumors in the same lesion. We present a case of a 47-year-old man with a lesion on his left cheek clinically characterized as a TF. However, the histopathological study reveals a collision tumor involving a TF and a melanocytic nevus. Collision tumors involving melanocytic nevi and hair follicle-related tumors have been previously reported, such as desmoplastic trichoepithelioma, epidermoid cyst, folliculosebaceous cystic hamartoma, and trichoadenoma.

Folliculosebaceous cystic hamartoma (FSCH) is a rare cutaneous hamartoma composed of dilated folliculosebaceous units and mesenchymal elements. It presents as a papule or nodule usually on the face and scalp, rarely on the genital or trunk area. Histologically, FSCH shares several similar features to sebaceous trichofolliculoma. We report one case of FSCH misdiagnosed as a neurofibroma. He was a 38-year-old man with a neurofibromatosis type I and a nodule on his left earlobe was excised under the impression of neurofibroma. Pathological examination revealed FSCH. Although FSCH is clinically not distinctive, awareness of the lesion is important to differentiate papulonodular or cyst-like cutaneous lesions.

Folliculosebaceous cystic hamartoma (FSCH) is a rare cutaneous hamartoma characterized by follicular, sebaceous, and mesenchymal elements. Folliculosebaceous cystic hamartoma is probably not as rare as previously thought and its inclusion in the differential diagnosis of asymptomatic skin colored papules or nodules is warranted, especially if it is present in the head and neck region.

Cutaneous hamartomas are tumor-like proliferations of tissue indigenous to the organ but arranged abnormally. There are examples in the literature of cutaneous hamartomas composed of a variety of different components. To our knowledge, there is no previous report of such cutaneous solitary neural hamartoma. Our case occurred in a 51-year-old man with pain and paresthesia in the right shoulder associated with a nodule that was surgically removed. There was no history of trauma, other skin nodules, neurofibromatosis, or tuberous sclerosis. Histologically, there was an unencapsulated nodule, composed of mature nerve bundles noted abnormally high within the papillary dermis, extending to the reticular dermis with periadnexal distribution. Immunohistochemically, the nerve bundles were positive for S-100, including the smaller nerve twigs, and the perineurium was highlighted by epithelial membrane antigen, reminiscent of normal peripheral nerves. Although, neural components including mature nerve bundles have been described in various cutaneous hamartomas, this represents a peculiar case of a cutaneous mature peripheral nerve hamartoma. Whether this is related to other entities of cutaneous hamartomas (ie, neurofollicular hamartoma, folliculosebaceous cystic hamartoma) is not yet apparent, although it is probably a unique entity.