Bowen disease with sebaceous differentiation arising from clonal seborrheic keratosis

We present a rare case of clonal seborrheic keratosis (SK) with focal Bowen disease (BD) (squamous cell carcinoma in situ) accompanied by sebaceous differentiation. An 89-year-old woman presented with a pale reddish-brown plaque on the left buttock. Histopathological examination of the excisional specimen revealed hyperkeratosis, acanthosis, and intraepidermal epithelioma. In some areas of the tumor, we observed proliferation of basaloid keratinocytes within the intraepidermal nests and pseudohorn cysts. This area was diagnosed as clonal SK. However, in other areas, the tumor cells within the intraepidermal nests showed nuclear pleomorphism, abnormal mitoses, dyskeratotic cells, and clumping cells, consistent with BD with a nested/clonal pattern (clonal BD). The SK and BD areas were contiguous with the transitional zone. Some nests within the BD area contained vacuolated cells with bubbly cytoplasm and scalloped nuclei, suggestive of sebaceous differentiation. Therefore, we made the diagnosis of clonal BD with sebaceous differentiation arising from clonal SK. All areas contained intraepidermal nests, which revealed that the lesions were not the result of accidental collision, but that the neoplastic cells in the intraepidermal nests of the SK transformed into BD and underwent sebaceous differentiation.

HPV-associated Vulvar Intraepithelial Carcinoma With Sebaceous Differentiation: Report of 2 Cases

Sebaceous carcinoma (SC) is a malignant neoplasm demonstrating sebocytic differentiation, commonly in the periocular area. Sebocytic differentiation is recognized by multivesicular cytoplasmic clearing with frequent nuclear scalloping. The vesicles can be highlighted by immunohistochemical stains against the perilipin family proteins including adipophilin. Extraocular SC is uncommon but well reported, often in the setting of Muir-Torre syndrome; however, vulvar SC is exceptionally rare. The literature review yielded only 12 prior cases of vulvar SC, all of which showed invasion. Here we report 2 additional similar cases from 2 different institutions of an intraepithelial carcinoma with sebaceous differentiation. Histologic examination of multiple specimens from both patients showed similar features: a multifocal intraepithelial basaloid nodular neoplasm sparing the basal layer with occasional pagetoid spread. The tumor cells demonstrated a high nuclear to cytoplasmic ratio, mitoses, variably foamy vacuolated cytoplasm, and nuclear indentation. Multiple specimens from both patients showed evidence of sebaceous differentiation (substantiated by adipophilin positivity in a membranous vesicular pattern in case 1 and by androgen receptor and epithelial membrane antigen positivity in case 2), and squamous differentiation (substantiated by p63/p40 and weak CK 5/6 expression), as well as human papillomavirus (HPV) association (substantiated by p16 block positivity and detection of high-risk HPV by in situ hybridization). One case was a true in situ lesion without evidence of invasion, and the other case was predominantly an in situ carcinoma with prominent adnexal extension and focal superficial invasion of <1 mm seen in one of multiple specimens. To our knowledge, these 2 cases are the first to show a vulvar SC/carcinoma with sebaceous differentiation that is predominantly limited to the epidermis, and the first documentation of HPV infection in vulvar sebaceous neoplasms. Vulvar intraepithelial carcinoma with sebaceous differentiation is the umbrella term we chose for this entity. Whether this is a true SC in situ that is HPV positive/driven, or a vulvar intraepithelial neoplasia with sebaceous differentiation, is not entirely clear. We emphasize the importance of looking for this morphology to avoid misclassification. Due to the rarity of cases, optimal treatment at this site has not been established.

Case Report: Treatment of Penile Intraepithelial Neoplasia in an Asian Male With Reconstructive Plastic Surgery

Intraepithelial neoplasia is a special type of squamous cell carcinoma occurring in the skin epidermis. The incidence of penile intraepithelial neoplasia in Asian males is rare. We report the clinical characteristics and treatment process of a case of penile intraepithelial neoplasia in a Chinese man. We treated the disease of this patient by surgical excision of the penile lesion and scrotal flap plastic surgery. After surgery, the shape of the penis was satisfactory, and there was no adverse effect on erection. The pathological results confirmed the diagnosis of penile intraepithelial neoplasia. The pathological features showed that the lesion tissue was covered with squamous epithelium and that there was severe atypical hyperplasia of the lesion epithelium, disordered arrangement of polarity, and an intact basement membrane. The removal of the lesions of penile intraepithelial neoplasia through a wider surgical resection range, combined with the stretchability of a scrotal flap, can achieve a good healing effect of the surgical wound and reduce the possibility of recurrence of penile intraepithelial neoplasia.

Twenty-Eight Cases of Extraocular Sebaceous Carcinoma: A Correlative Clinicopathological and Immunohistochemical Analysis of Extraocular Sebaceous Carcinomas and Benign Sebaceous Gland Tumors

ABSTRACT

Extraocular sebaceous carcinoma (ESC) is a rare appendiceal skin tumor. In contrast to ocular sebaceous carcinoma, information about the exact cellular architecture of these lesions is scarce and the histogenesis of ESC is unknown. Here, we extend our previous study and investigate 28 extraocular carcinomas in comparison to 54 benign sebaceous tumors and 8 cases of normal sebaceous glands using a broad spectrum of antibodies against p63, several keratins, adipophilin, EMA, Ki67, androgen receptor, and mismatch repair proteins. This observational study demonstrates that p63- and K5/14-positive basaloid cells are key cells in normal sebaceous gland and in all sebaceous tumors and that these basaloid cells give rise to EMA+, adipophilin+ sebocytes, and K5/14+, K7±, K10± ductal structures. Finally, about half of ESC is associated with superficial in situ neoplasia, which provides evidence that at least part of these carcinomas arises from flat superficial in situ carcinoma. In contrast to the normal sebaceous gland, about half of all sebaceous tumors lack keratin K7. MMR protein IHC-profiles role will be discussed.

Ocular Sebaceous Carcinoma In Situ With Biphenotypic Differentiation: A Reappraisal of the Alternative Origin of the Tumor

Ocular sebaceous carcinoma is an uncommon, aggressive tumor arising from the Meibomian gland, Zeis gland, or sebaceous glands in the caruncle or eyelashes. We described a rare case of sebaceous carcinoma in situ in a 51-year-old female that was characterized by intraepithelial growth of sebaceous carcinoma cells with no invasive carcinoma in the underlying sebaceous glands. Early stromal invasion was identified that featured 2 distinctive but focally intermixed populations of sebaceous carcinoma cells and squamous carcinoma cells. The 2 populations of cells exhibited their respective distinct immunophenotype but both showed strong overexpression of p53. This case provides evidence to support the hypothesis that some ocular sebaceous carcinoma may arise from intraepithelial pluripotent stem cells.

Spatial analysis of p63, K5 and K7 defines two groups of progenitor cells that differentially contribute to the maintenance of normal sebaceous glands, extraocular sebaceous carcinoma and benign sebaceous tumors

The histogenesis of extraocular sebaceous carcinomas is - in contrast to ocular sebaceous carcinomas - unclear, and information about the exact cellular architecture of these lesions and even of the normal sebaceous gland is still scarce. This study attempts to elucidate the histogenesis of sebaceous tumors, using multicolor immunofluorescence stainings to analyze 21 cases of sebaceous tumors (six each of extraocular sebaceous carcinoma, sebaceous adenoma and sebaceoma, and three cases of steatocystomas) and eight cases of normal sebaceous glands for p63, several keratins, androgen receptor, adipophilin, epithelial membrane antigen (EMA) and Ki-67. The data of this observational study provide evidence for the existence of two subpopulations of progenitors in normal sebaceous glands: (i) p63⁺ K5⁺ progenitors which generate the K10⁺ luminal cells of sebaceous ducts; and (ii) p63⁺ K5⁺ K7⁺ progenitors which finally generate K7⁺ adipophilin⁺ EMA⁺ sebocytes. Without exception, all types of sebaceous tumors contained p63⁺ K5⁺ cells. Furthermore, these tumors showed a cellular hierarchy and differentiation to adipophilin⁺ and/or EMA⁺ mature sebocytes and to K10⁺ ductal cells through intermediary cells. Notably, a considerable number of sebaceous tumors lack the K7 pathway of cell maintenance in the normal sebaceous lobule. Based on our data, we propose a cellular algorithmic model of the hierarchy of normal sebaceous glands and of sebocytic tumors in which p63⁺ K5⁺ cells play a major role.

Sebaceous cell differentiation in a canine oral papilloma

Papillomas caused by viral infection are well-known tumors in animals. Microscopic features typically include neoplastic epithelium with hyperkeratosis and koilocytes. An 8-y-old castrated male Shih Tzu dog was presented with a small exophytic mass on the external upper lip. The mass was diagnosed as a viral papilloma based on microscopic and immunohistochemical examination. Sebaceous cell differentiation was found in the neoplastic epithelium of the tumor, which is a rare finding in humans or animals.

Multiple viral plaques with sebaceous differentiation associated with an unclassified papillomavirus type in a cat

CASE HISTORY AND CLINICAL FINDINGS A 15-year-old neutered male domestic short-haired cat was presented due to multiple 0.5-2 cm-diameter crusting plaques in the left preauricular region, over the bridge of nose, and in the right periocular region. The plaques did not appear to cause discomfort. HISTOPATHOLOGICAL FINDINGS Biopsy samples of four plaques were examined histologically. Three plaques consisted of well-demarcated foci of mild epidermal hyperplasia overlying markedly hyperplastic sebaceous glands. Approximately 60% of the hyperplastic cells contained a large cytoplasmic vacuole that ranged from being clear to containing prominent grey-blue fibrillar material. The fourth plaque was composed solely of epidermal hyperplasia, consistent with previous descriptions of feline viral plaques. MOLECULAR BIOLOGY Papillomavirus DNA was amplified from all four plaques using PCR. A single DNA sequence was amplified from the plaques with sebaceous differentiation. This sequence was identical to the FdPV-MY sequence previously suggested to be from a putative unclassified papillomavirus type. Felis catus papillomavirus type 2 sequences were amplified from the plaque typical of feline viral plaques. Immunohistochemistry to detect p16^CDKN2A protein (p16) showed marked immunostaining throughout the hyperplastic epidermis and adnexal structures within the plaques with sebaceous differentiation. DIAGNOSIS Multiple feline viral plaques with variable sebaceous differentiation. CLINICAL RELEVANCE Feline viral plaques with sebaceous differentiation have not been previously reported in cats. The presence of unique cell changes within these lesions, the detection of an unclassified papillomavirus type, and the p16 immunostaining within these plaques suggest that they may have been caused by the papillomavirus that contains the FdPV-MY sequence.

Topics in histopathology of sweat gland and sebaceous neoplasms

This article reviews several topics regarding sweat gland and sebaceous neoplasms. First, the clinicopathological characteristics of poroid neoplasms are summarized. It was recently reported that one-fourth of poroid neoplasms are composite tumors and one-fourth are apocrine type lesions. Recent progress in the immunohistochemical diagnosis of sweat gland neoplasms is also reviewed. CD117 can help to distinguish sweat gland or sebaceous tumors from other non-Merkel cell epithelial tumors of the skin. For immunohistochemical differential diagnosis between sweat gland carcinoma (SGC) other than primary cutanesous apocrine carcinoma and skin metastasis of breast carcinoma (SMBC), a panel of antibodies may be useful, including p63 (SGC⁺ , SMBC^- ), CK5/6 (SGC⁺ , SMBC^- ), podoplanin (SGC⁺ , SMBC^- ) and mammaglobin (SGC^- , SMBC⁺ ). Comparison of antibodies used for immunohistochemical diagnosis of sebaceous carcinoma (SC) suggests that adipophilin has the highest sensitivity and specificity. Some authors have found that immunostaining for survivin, androgen receptor and ZEB2/SIP1 has prognostic value for ocular SC, but not extraocular SC. In situ SC is rare, especially extraocular SC, but there have been several recent reports that actinic keratosis and Bowen's disease are the source of invasive SC. Finally, based on recent reports, classification of sebaceous neoplasms into three categories is proposed, which are sebaceoma (a benign neoplasm with well-defined architecture and no atypia), borderline sebaceous neoplasm (low-grade SC; an intermediate tumor with well-defined architecture and nuclear atypia) and SC (a malignant tumor with invasive growth and evident nuclear atypia).