Role of Immunohistochemistry in the Diagnosis of Sebaceous Carcinoma: A Clinicopathologic and Immunohistochemical Study

Androgen Receptor Immunohistochemistry is Superior to PRAME for the Differentiation of Sebaceous Carcinoma From Primary Cutaneous Basaloid Mimics

ABSTRACT

Cutaneous sebaceous neoplasia comprises a spectrum of disease ranging from benign adenomas to malignant carcinomas. The hallmark of these lesions is sebaceous differentiation. However, poorly-differentiated sebaceous carcinoma (SC), which lacks significant overt sebaceous differentiation, can show morphologic overlap with a variety of other basaloid cutaneous neoplasms. The accurate classification of SC is essential not only for diagnosis, but also because of the potential association with Muir-Torre syndrome. Androgen receptor (AR) is a sensitive, but not entirely specific immunohistochemical marker that has been used for the diagnosis of SC. PReferentially expressed Antigen in MElanoma (PRAME) demonstrates strong cytoplasmic labeling of mature sebocytes and has been reported to be expressed in a variety of sebaceous neoplasms, including in the basaloid cell component. Therefore, we sought to compare the diagnostic use of cytoplasmic PRAME expression with that of AR for the distinction of SC from a cohort of basaloid cutaneous mimics; namely basal cell carcinoma, basaloid squamous cell carcinoma, pilomatricoma, cutaneous lymphadenoma, and extra-mammary Paget disease. We report that cytoplasmic PRAME expression is uncommon in poorly differentiated SC, and although specific, it shows very low sensitivity (22%). In contrast, AR was moderately sensitive (66%) and highly specific (92%) for the distinction of SC from basaloid mimics. These attributes, in addition to the nuclear expression of AR in the sebocytic and basaloid components of SC, suggest that AR is superior to PRAME for the diagnosis of SC.

Sebaceous carcinoma: an updated review of pathogenesis, diagnosis, and treatment options

Sebaceous carcinoma (SC) is a very rare and aggressive form of skin cancer that arises from the sebaceous glands. SC can occur anywhere on the body, but most commonly affects the head and neck, especially the upper eyelid. SC is the third most common malignancy of the eyelid and has the potential to metastasize and be fatal; therefore, it is vital for dermatologists to remain acquainted with this malignancy and its most current treatment options. Most commonly presenting as a painless lump or thickening of skin on the eyelid, SC has an insidious progression that may not prompt the patient to seek medical attention immediately. To avoid the potential of metastasis, early diagnosis and treatment is paramount. To assess if the cancer has spread, ophthalmology, imaging, and sentinel lymph node biopsy are recommended. This article provides a comprehensive review of SC's pathogenesis, current diagnostic methods, and treatments, including wide local excision, Mohs micrographic surgery, orbital exenteration, radiation, and other topicals. The prognosis of SC depends on several factors, including size, location, stage, and treatment method. After treatment of the neoplasm, diligent post-treatment surveillance remains the cornerstone of patient care. Continued dermatologic follow-ups are essential for early detection of reoccurrence, ensuring timely intervention and optimal long-term outcomes. In conclusion, this comprehensive review aims to equip dermatologists and other physicians with a nuanced understanding of SC, enabling them to provide effective care to support patients encountering this malignancy.

Sebaceous Carcinoma of the Wrist in an Elderly Woman: A Case Report

Sebaceous carcinoma is a rare, aggressive cutaneous malignancy most commonly arising from the periocular area. Extraocular locations of sebaceous carcinomas, particularly outside of the head and neck region, are rare and not well-described. We report a case of an 89-year-old Caucasian female with sebaceous carcinoma of the right wrist. She initially presented with a 1.2-centimeter friable nodule on the right wrist. Initial shave biopsy and subsequent pathologic evaluation revealed a basaloid neoplasm with sebaceous differentiation, atypia, and frequent mitoses, consistent with sebaceous carcinoma. The presented case reviews common clinical features and the pertinent histopathology of ocular and extraocular sebaceous carcinoma and provides a literature review of diagnosis, prognosis, and treatment.

Case Report: Optimum excision with split skin graft closure in the management of penile sebaceous carcinoma

Sebaceous carcinoma (SC) is a rare malignant skin neoplasm derived from the meibomian gland of adnexal epithelium, which is frequently confused with basal cell carcinoma (BCC), exhibiting sebaceous differentiation and commonly found in the head and neck regions. We report a case of penile sebaceous carcinoma, an extremely rare anatomical site for SC. A 68-year-old man presented with a 4-month history of painless, non-healing ulcerated nodules over the left side of the penile shaft. Wedge biopsy showed adenocarcinoma with signet ring differentiation. We proceeded with wide local excision (WLE) of the lesion with the inclusion of the indurated skin and 5 mm of normal margin, followed by primary closure of the scrotal defect and split skin grafting of the penile shaft by using a thigh skin donor. The final histopathological examination revealed sebaceous carcinoma with pagetoid spread. The patient achieved recurrence-free survival without any form of adjuvant therapy after 4 years of follow-up.

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.

Primary Sebaceous Carcinoma of the Eyebrow: A Case Report

Sebaceous carcinoma (SC) is an uncommon but aggressive malignancy and has a specific anatomic preference for the ocular region, especially the eyelids. However, periocular SC originated from the eyebrow is rare, which may cause poorer outcomes due to a greater likelihood of orbital invasion and excessive tumor volume. In the present case, we exhibited a 68-year-old male presenting with a large solid mass in his right eyebrow region developing in ten months. Based on the patient's history, clinical conditions, orbital computed tomography (CT) and magnetic resonance imaging (MRI) scan results, a malignant tumor was suspected preliminarily. Excisional biopsy was performed, and the histopathologic examination and immunohistochemistry (IHC) staining of the tumor revealed SC. The patient declined the enlarged surgery recommended next and ended up with death caused by the distant metastasis of SC. The case highlighted the fact that despite its rarity, SC should be considered as a differential diagnosis of tumors located in the eyebrow region and histopathologic evaluation must be performed to reach a definite diagnosis. Ophthalmologists are supposed to have a comprehensive understanding of the clinicopathological characteristics of this disease and help patients accept the appropriate treatments promptly via properly and adequate communication if necessary.

Upregulated MYC expression and p53 mutations may contribute to the oncogenesis of canine Meibomian gland carcinomas

Sebaceous carcinomas of the human ocular adnexa commonly exhibit pagetoid spread, mutations in tumor-suppressor genes, and protooncogene copy number gain. Sebaceous carcinomas are rarely reported in other species, and while the Meibomian gland (MG) represents the most common ocular adnexal structure of the canine eyelid to develop neoplasia, most are clinically and histologically benign. The objective of this study was to compare molecular features of canine MG carcinomas and adenomas. Two retrospectively identified MG carcinomas were subject to immunohistochemistry and qPCR. When compared with normal glands, MYC was upregulated in benign and malignant MG neoplasms. Aberrant p53 expression was restricted to the nuclei of intraepithelial neoplastic cells in MG carcinomas. Adipophilin expression was diminished in MG neoplasms compared with the normal MG. Our findings, if confirmed in a larger cohort of cases, could suggest that MG oncogenesis in a dog may exhibit similar molecular features as their human counterparts.

Sebaceous Carcinoma of the Penis: A Rare, Dangerous Clinical Entity and the Importance of Immunohistochemistry in Diagnosis

We report a very rare case of pathologically confirmed sebaceous carcinoma of the glans penis with multiple areas of lymphovascular and perineural invasion and multiple lymph node metastases. The importance of immunohistochemical staining in diagnosis is also reviewed.

Diagnostic Accuracy of GATA6 Immunostaining in Sebaceous Tumors of the Skin

The accurate diagnosis of skin adnexal neoplasms is sometimes challenging but is necessary because medical management and follow-up may differ between tumors. GATA6 transcription factor has been identified as a new marker of the upper folliculosebaceous compartment (lower infundibulum, junctional zone and isthmus, and upper sebaceous gland) in the human skin. We aimed to determine the diagnostic accuracy of GATA6 immunostaining to diagnose sebaceous tumors compared with that to diagnose other adnexal and nonadnexal cutaneous neoplasms. We conducted a retrospective, evaluator-nonblinded study comparing the reference standard (diagnosis by an expert dermatopathologist) with GATA6 immunostaining to identify sebaceous tumors in a cohort containing 234 different tumors. The GATA6 expression score was significatively higher in sebaceous than that in nonsebaceous tumors. In addition, tumors originating from the upper hair follicle showed positive results for GATA6 staining; however, they showed lower GATA6 expression scores. Detection of sebaceous tumors using GATA6 positivity had a sensitivity of 95.7% (95% confidence interval [95% CI], 85.8-99.2), specificity of 80.8% (95% CI, 74.5-85.8), positive predictive value of 55.6% (95% CI, 44.7-65.9), and negative predictive value of 98.7% (95% CI, 95.4-99.8). GATA6 showed similar sensitivity to adipophilin, the reference marker; however, the specificity of GATA6 was higher, as observed in a cohort of 106 tumors enriched in squamous cell carcinomas with clear-cell histology. In addition, GATA6 positivity was assessed in 39 sebaceous carcinomas and compared with epithelial membrane antigen (EMA), CK7, and androgen receptor (AR) staining results. Although CK7 staining displayed lower diagnostic performances, GATA6 staining showed comparable results as EMA and AR. Finally, we found GATA6 expression in skin metastases of gastrointestinal origin, whereas GATA6 was absent in metastases originating from breast or lung cancers. Overall, our work identified GATA6 immunostaining as a new diagnostic tool for sebaceous tumors.

Sebaceous carcinoma of trunk with bilateral axillary lymph node metastasis: a rare presentation of malignant adnexal tumor in young adult

Malignant adnexal tumors of skin are rare. Sebaceous carcinoma—a rare and aggressive cutaneous tumor—is frequently located in the periorbital region. Malignant adnexal tumors of sebaceous carcinoma type on trunk with axillary lymph node and distant metastasis in young adult is rare. The incidence of extraocular sebaceous carcinoma has been expected to be 0.06 per 100 000 person-years with an increased incidence in elderly patients and men. With a note of mimicking benign dermatologic conditions, definitive diagnosis of sebaceous carcinomas is often hindered, increasing morbidity and mortality for patients. Herein, we present a case of a 35-year-old man with a large ulcero-proliferating lesion of trunk region previously resected for a small swelling and eventually presented with the recurrent lesion and diagnosed as sebaceous carcinoma of trunk with bilateral axillary lymphnode and distant bone metastasis demonstrating several diagnostic and management challenges.

Sebaceous Carcinomas: A Clinicopathological Comparison of Ocular and Extraocular Variants

ABSTRACT

Sebaceous carcinomas (SC) are rare tumors and are currently classified into ocular and extraocular variants. Both variants of SC have very different clinical behavior and different histomorphologic appearance; however, published data are confounding as literature describes prognosis of both variants is similar or even that extraocular variants are more aggressive. In this study we evaluated the clinical and the histopathology of ocular and extraocular SC to confirm the difference between them. We performed a retrospective review of SC in which we studied the clinical and histomorphologic features of 106 cases, including 39 cases of ocular SC and 67 cases of extraocular SC. Only 2/67 cases of extraocular SC had multiple recurrences and none of them metastasized as opposed to our cases of ocular SC wherein 21/39 cases were locally aggressive with multiple recurrences and 5 cases metastasized. Histologically, both neoplasms showed major distinct morphologic features including poor differentiation in cases of ocular SC and well-differentiated tumors in the extraocular anatomic sites. To the best of our knowledge, this is the first case series of SC that compares the clinicopathologic features of ocular and extraocular variants. Awareness of such discrepancy is key to understand this disease and to possibly diagnose and manage these patients accordingly.

Lipid Droplet Accumulation Independently Predicts Poor Clinical Prognosis in High-Grade Serous Ovarian Carcinoma

Simple Summary

High-grade serous carcinoma (HGSOC) is the most aggressive subtype of ovarian cancer and accounts for the vast majority of advanced stage cases. Intracellular accumulation of lipids as lipid droplets has been recognized as one of the characteristics of cancers and implicated in poor prognosis of several cancers, such as human melanomas. Here, we investigated the relationship between prognosis and lipid accumulation in HGSOC, and found that enhanced lipid accumulation in HGSOC tissues significantly correlated with poor prognosis. In cell-based assays with human ovarian cancer cells, we provide evidence that aerobic glycolysis, which is one of the characteristic metabolic abnormalities in cancer, induced lipid accumulation within cancer cells and targeting the lipid accumulation could suppress cancer cell proliferation. Thus, our results propose abnormal lipid accumulation as a negative indicator of HGSOC prognosis and a novel therapeutic target.

Abstract

High-grade serous ovarian carcinoma (HGSOC) is an epithelial cancer that accounts for most ovarian cancer deaths. Metabolic abnormalities such as extensive aerobic glycolysis and aberrant lipid metabolism are well-known characteristics of cancer cells. Indeed, accumulation of lipid droplets (LDs) in certain types of malignant tumors has been known for more than 50 years. Here, we investigated the correlation between LD accumulation and clinical prognosis. In 96 HGSOC patients, we found that high expression of the LD marker adipophilin was associated with poor progression-free and overall survival (p = 0.0022 and p = 0.014, respectively). OVCAR-3 ovarian carcinoma cells accumulated LDs in a glucose-dependent manner, which suggested the involvement of aerobic glycolysis and subsequently enhanced lipogenesis, with a result being LD accumulation. The acyl-CoA: cholesterol acyltransferase 1 inhibitor K604 and the hydroxymethylglutaryl-CoA reductase inhibitor pitavastatin blocked LD accumulation in OVCAR-3 cells and reduced phosphorylation of the survival-related kinases Akt and ERK1/2, both of which have been implicated in malignancy. Our cell-based assays thus suggested that enhanced aerobic glycolysis resulted in LD accumulation and activation of survival-related kinases. Overall, our results support the idea that cancers with lipogenic phenotypes are associated with poor clinical prognosis, and we suggest that adipophilin may serve as an independent indicator of a poor prognosis in HGSOC.

Clear Cell Proliferations of the Skin: A Histopathologic Review

ABSTRACT

Cutaneous clear cell proliferations encompass a heterogenous group of several primary cutaneous neoplasms and metastatic tumors with different histogenesis. Many of these clear cell proliferations may seem strikingly similar under the microscope resulting in challenging diagnosis. In many of these clear cell lesions, the reason for the clear or pale appearance of proliferating cells is unknown, whereas in other ones, this clear cell appearance is due to intracytoplasmic accumulation of glycogen, mucin, or lipid. Artifacts of tissue processing and degenerative phenomenon may also be responsible for the clear cell appearance of proliferating cells. Awareness of the histopathologic findings as well as histochemical and immunohistochemical techniques are crucial to the accurate diagnosis. This review details the histopathologic features of clear cell cutaneous proliferations, classifying them according their type of differentiation and paying special attention to the histopathologic differential diagnosis among them.

GLUT1 Expression in Cutaneous Sebaceous Lesions Determined by Immunohistochemical Staining Patterns

GLUT1 is a membrane associated carrier protein that functions in the physiologic transport of glucose across cell membranes. Multiple studies have shown an increased GLUT1 expression in various tumor types and a role in cancer prognosis. The aim of this study was to determine whether cutaneous sebaceous lesions have a differential expression of GLUT1 by immunohistochemistry (IHC). GLUT1 IHC was performed on excision specimens of ten cases of sebaceous carcinoma, nine of sebaceoma, ten of sebaceous adenoma, and ten of sebaceous hyperplasia. Intense, diffuse cytoplasmic staining was observed in sebaceous carcinoma. The pattern of GLUT1 staining in sebaceomas and sebaceous adenomas consisted of a gradient of intense cytoplasmic staining in the basaloid cells with a decreased intensity to membranous staining only and absent staining in mature sebaceous cells. In lesions of sebaceous hyperplasia, GLUT1 staining outlined the basal layer of each gland; cytoplasmic staining was minimal to absent. Increased cytoplasmic staining of GLUT1 may correlate with cellular metabolic and proliferative activity. GLUT1 has potential utility in differentiating sebaceous lesions.

Establishment and Characterization of a Novel Human Ocular Adnexal Sebaceous Carcinoma Cell Line

Purpose

Sebaceous carcinoma (SC) is a malignant eyelid tumor of the ocular adnexa that is primarily treated via surgical excision. Few therapies exist in advanced cases, and medical therapy is limited because of our incomplete understanding of SC biology. Herein, we describe a technique to culture human ocular adnexal SC for use as an in vitro model.

Methods

Human ocular adnexal SC tumor cells were isolated from a patient undergoing orbital exenteration surgery and named Bascom Palmer 50 (BP50). They were cultured in Dulbecco's modified Eagle medium/nutrient mixture F-12 supplemented with 10% fetal bovine serum and antibiotics and were maintained at 37°C in humidified 5% CO₂. The cells were characterized by immunohistochemistry, exome sequencing, and short tandem repeats analysis. In vitro drug screening against mitomycin-C (MMC) was performed using a cell viability assay.

Results

BP50 grew past 40 passages with a doubling time of 52.3 hours. Immunocytochemical staining revealed expression of SC-associated markers adipophilin, epithelial membrane antigen, p53, and androgen receptor. Whole exome sequencing showed a significant carryover in somatic mutations between the tumor tissue and corresponding cell line, revealing genetic markers consistent with SC. MMC affected cell viability in a dose-dependent manner.

Conclusions

BP50 displays characteristics of ocular adnexal SC and therefore may facilitate improved understanding of SC biology and the high throughput assessment of novel therapeutic compounds and new drug combinatorial approaches targeted for this disease.

Translational Relevance

Drug screening with MMC against these cells shows in vitro evidence to support its continued clinical use in SC.

Sebaceous carcinoma of the right palate: case report and literature review

Considering the low incidence rates of primary sebaceous carcinoma (SC) of extraorbital sites, let alone those occur in intraoral sites, clinicopathological characteristics and histogenesis are not fully understood. In the present case, a maxillary mass was presented and a low-grade malignant tumor was suspected according to the CT scans, preoperative FNA, and clinical conditions. Other carcinomas, including acinar cell carcinoma (ACC), basaloid cell carcinoma (BCC), SCC, mucoepidermoid carcinoma, and epithelial-myoepithelial carcinoma (EMC), were also considered before surgery. Due to the rare occurrence of SC and no preoperative suspects, a fresh sample was not kept. Sadly, thus cause those special stains (e.g., Oil Red O and Sudan IV) which form the primary basis for a diagnosis of SC in academic circles were missing. A comprehensive literature review identified only 10 cases of intraoral SC, of which the primary sites reported in the English literature were the buccal mucosa, mouth floor, upper labial mucosa, and tongue. Due to an absence of specific biomarkers and simulated characters, histochemistry and immunohistochemistry such as PAS, CK, EMA, p63, p53, S-100, calponin, CD117, Ki-67, a-SMA, and AR form the diagnostic standard of SC. Postoperative immunohistochemistry of our case showed S100(-), Ki-67(-), calponin(-), CD117(-), CK20(-), PAS(-), AR(+), CK(+), CK5/6(+), P53(+), P63(+), a-SMA (+). Thus the diagnosis of SC was finally made. Through discussing the findings of our case and reviewing literature, we present the histological features and discuss possible outstanding biomarkers of this neoplasm.

Diagnosis and analysis of a sebaceous gland tumour of the external acoustic meatus in a Cocker Spaniel dog

Sebaceous gland tumour (SGT) is a rare tumour with a low incidence rate, which mainly occurs in the eyelid and periocular sebaceous gland. In 2019, our laboratory received a case involving a sebaceous gland tumour of the external auditory meatus for pathological diagnosis. It is a rare malignant tumour in the whole body. Data regarding a sebaceous gland tumour in the dogís external auditory meatus are few. This case is instructive for veterinary diagnosis and treatment. The dog recovered well after surgery at the outpatient department, and no recurrence was observed in the follow-up visit one year later. This study will help the identification of SGT in Spaniel dogs.

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.

Management of recurrent sebaceous gland carcinoma

OBJECTIVE

To evaluate the incidence and management of recurrent periocular sebaceous gland carcinoma at a tertiary ocular oncology service in the United Kingdom.

METHODS

This was a retrospective cohort study of 62 patients with sebaceous gland carcinoma treated between 2004 and 2017. A total of 10 eyes were treated for local recurrence. The following variables were recorded: age and sex of patient; tumour location, histological subtype; recurrence type; treatment and outcome.

RESULTS

Of the 62 cases with eyelid SGC, 10 (16%) had recurrences during the study period and satisfied inclusion criteria. There were six (60%) females and four males in the recurrent group. The mean time interval between initial excision and tumour recurrence was 37 months (median 23 months; range 4 to 84 months). Four patients received cryotherapy to the lids and conjunctiva to control recurrent disease and two patients were treated with topical or intralesional chemotherapy. Four patients (40%) underwent orbital exenteration during the study period. Metastasis occurred in 20% over a mean follow-up of 113 months (median 106; range 47-184 months).

CONCLUSIONS

The risk factors for local recurrence of SGC after wide excision with paraffin section control were reported, and an approach to these recurrent lesions was proposed. The results of this study will help guide surgeons dealing with the medical and surgical conundrum of recurrent disease. The risk of recurrence is highest in the first 2 years after initial excision.

Eyelid basal cell carcinoma with neuroendocrine differentiation: a case report and literature review

Basal cell carcinoma (BCC) is the most common type of malignant tumor in the periocular region. BCCs with neuroendocrine differentiation in the periocular region, however, have not been described in the literature.We present a retrospective case review of a patient with an eyelid BCC with neuroendocrine differentiation. Demographical, clinical, radiological, surgical, histological, and follow-up data are presented.The patient presented with a slow-growing lesion of the eyelid with associated epiphora and dull ache. Initial incisional biopsy of the lesion revealed an infiltrating carcinoma composed of epithelial cells. Immunohistochemistry showed that the tumor was positive for p40, Ber-Ep4, neuron specific enolase (NSE), chromogranin A, CD56 (NCAM), and synaptophysin. The pathology from the margin-controlled excision showed basosquamous cell carcinoma with neuroendocrine differentiation. Tumor recurrence was not detected clinically at the post-operative six-month review.BCC with neuroendocrine marker positivity represents an important diagnostic differential for rare eyelid carcinomas such as primary cutaneous neuroendocrine carcinoma and metastatic small cell carcinoma that have a poor prognosis. The prognostic importance of neuroendocrine marker positivity in BCCs is uncertain. The present case provides further evidence for neuroendocrine differentiation in BCCs.

Adipophilin expression in cutaneous malignant melanoma is associated with high proliferation and poor clinical prognosis

Adipophilin (ADP) is a primary protein component of lipid droplets (LDs). For more than half a century, certain types of cancer cells have been known to contain LDs in their cytoplasm. However, the pathological significance of ADP or LDs in cancer remains unclear. In the present study, we investigated the association between ADP and other pathological characteristics in cutaneous malignant melanomas to clarify the role of ADP in melanoma cells. We immunostained whole paraffin sections of primary cutaneous melanomas obtained from 90 cases for ADP, after which we analyzed the correlation between ADP immunohistochemistry (IHC) and patient survival data. We also studied the relationship between the ADP IHC score and in situ hybridization (ISH) score of ADP mRNA, and the Ki67-labeling index (Ki67-LI) by using tissue microarrays consisting of 74 primary cutaneous malignant melanomas, 19 metastasizing melanomas, and 29 melanocytic nevi. Finally, we analyzed the relationship between ADP expression and cell proliferation in cutaneous melanoma cell lines. We found that high ADP expression was associated with poor metastasis-free survival, disease-specific survival, and overall survival rates of patients with cutaneous melanomas (P < 0.05). By linear regression analysis, ADP IHC was correlated with increasing ADP mRNA ISH H-scores and Ki67-LI scores in melanocytic lesions (P < 0.01). ADP IHC and ADP ISH H-scores and Ki67-LI scores were greater in pT3-4 melanomas than in pT1-2 melanomas. In cell-based assays, cells with increased ADP expression showed higher proliferation rates compared with those of low-ADP cells. Thus, ADP expression in malignant melanoma was significantly associated with high cell proliferation and poor clinical prognosis. Our results thus indicate a significant association between ADP and melanoma progression, and we propose that ADP may be a novel marker of aggressive cutaneous melanoma with a lipogenic phenotype.

Sebaceous carcinoma: evidence-based clinical practice guidelines

Sebaceous carcinoma usually occurs in adults older than 60 years, on the eyelid, head and neck, and trunk. In this Review, we present clinical care recommendations for sebaceous carcinoma, which were developed as a result of an expert panel evaluation of the findings of a systematic review. Key conclusions were drawn and recommendations made for diagnosis, first-line treatment, radiotherapy, and post-treatment care. For diagnosis, we concluded that deep biopsy is often required; furthermore, differential diagnoses that mimic the condition can be excluded with special histological stains. For treatment, the recommended first-line therapy is surgical removal, followed by margin assessment of the peripheral and deep tissue edges; conjunctival mapping biopsies can facilitate surgical planning. Radiotherapy can be considered for cases with nerve or lymph node involvement, and as the primary treatment in patients who are ineligible for surgery. Post-treatment clinical examination should occur every 6 months for at least 3 years. No specific systemic therapies for advanced disease can be recommended, but targeted therapies and immunotherapies are being developed.

Eyelid abscess masking underlying sebaceous cell carcinoma

Sebaceous cell carcinoma is well known as the "great masquerader" mimicking other benign or malignant eyelid conditions and lesions. We present a case of a middle age male presenting with a subacute left upper lid abscess who was ultimately diagnosed with malignant sebaceous cell carcinoma after incision and drainage and treatment with broad spectrum antibiotics. This case highlights the deceptive clinical and radiographic appearance of this tumor and the importance of histologic examination in atypical or refractory periorbital abscesses.

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.

Immunohistochemistry in Dermatopathology and its Relevance in Clinical Practice

Immunohistochemistry (IHC) is an important diagnostic tool in histopathology. Dermatopathology is a rapidly developing subspecialty of histopathology. Although IHC is not widely used in routine dermatopathology practice, its application is gradually increasing. IHC is used to differentiate two conditions with similar morphology, to confirm a diagnosis as well as to assess prognosis. It is more commonly used for neoplastic conditions like melanocytic, hematolymphoid, and spindle cell tumors, although uses can be very wide. Although IHC can aid in diagnosis, sometimes interpretation can be difficult as there may be overlapping findings. Thus, IHC should not be interpreted in isolation and should be done in the context of clinical and histological findings. In this review, we have discussed the uses of various immunohistochemical markers in dermatopathology in the light of current literature and their clinical relevance.

Intraoral Sebaceous Carcinoma: Case Report of a Rare Tumor Emphasizing the Histopathological Differential Diagnosis

Background

Sebaceous carcinoma (SC) is an uncommon cutaneous malignancy, usually occurring predominantly in the eyelids and only occasionally involving the oral cavity. Sebaceous carcinoma (SC) is a rare malignancy. Only 10 cases of sebaceous carcinoma of the oral cavity have been reported so far.

Case Presentation

A 40-year-old female presented with a mass on the left side of the middle third of the face. Radiographic findings were inconclusive. Resection of the mass was consistent with the diagnosis of primary sebaceous carcinoma.

Conclusion

Intraoral sebaceous carcinoma is uncommon. Due to its varied clinical appearance and presence of a diverse histopathologic appearance, the diagnosis is quite often confounding and elusive. Hence, it is imperative to familiarize oneself about various aspects of this rare tumor for earlier diagnosis, to improve the chances of patient's survival.

Dermoscopic features distinctive for extraocular sebaceous carcinoma

We examined dermoscopic features of three cases of extraocular sebaceous carcinoma and reviewed the literatures. The yellowish structures, polymorphous vessels and ulceration were common findings in our cases and all cases of the previous reports. The appearance of whitish-pink areas has not been described previously. Our results suggested that the combination of four dermoscopic features, whitish-pink areas, yellowish structures, polymorphous vessels and ulceration might be distinctive in extraocular sebaceous carcinoma.

Histologic Mimics of Basal Cell Carcinoma

CONTEXT

- Basal cell carcinoma (BCC) is the most common human malignant neoplasm and is a frequently encountered diagnosis in dermatopathology. Although BCC may be locally destructive, it rarely metastasizes. Many diagnostic entities display morphologic and immunophenotypic overlap with BCC, including nonneoplastic processes, such as follicular induction over dermatofibroma; benign follicular tumors, such as trichoblastoma, trichoepithelioma, or basaloid follicular hamartoma; and malignant tumors, such as sebaceous carcinoma or Merkel cell carcinoma. Thus, misdiagnosis has significant potential to result in overtreatment or undertreatment.

OBJECTIVE

- To review key features distinguishing BCC from histologic mimics, including current evidence regarding immunohistochemical markers useful for that distinction.

DATA SOURCES

- Review of pertinent literature on BCC immunohistochemistry and differential diagnosis.

CONCLUSIONS

- In most cases, BCC can be reliably diagnosed by histopathologic features. Immunohistochemistry may provide useful ancillary data in certain cases. Awareness of potential mimics is critical to avoid misdiagnosis and resulting inappropriate management.

Sebaceous lesions of the skin

Sebaceous differentiation is commonly seen in cutaneous neoplasms, both in the context of lesions showing predominantly sebaceous differentiation (e.g., sebaceous adenoma, sebaceoma and sebaceous carcinoma), or as more focal sebaceous components in neoplasms with other primary lines of differentiation. Sebaceous changes can also be a component of benign cystic lesions or epidermal tumours, and sebaceous hyperplasia is commonly encountered. This review is intended to provide an overview of the cutaneous lesions with sebaceous differentiation, with a particular emphasis on facilitating histological diagnosis of neoplasms. In addition, the role of immunohistochemical studies is outlined, as well as the evaluation of potential cases of Muir-Torre syndrome.

Sebaceous Neoplasms

Sebaceous skin tumors are classified into sebaceous adenoma, sebaceoma, and sebaceous carcinoma. An additional group of cystic sebaceous tumors indicate the Muir-Torre syndrome (MTS). Cystic sebaceous tumors are considered as morphologic variants of the 3 main categories. Multilineage adnexal tumors with partly sebaceous differentiation may pose a challenge to categorize. Sebaceous hyperplasia and nevus sebaceus are not considered as true sebaceous tumor entities. Recently, attention has been drawn to morphologic clues of sebaceous differentiation. Immunohistochemistry using the mismatch repair proteins and/or genetic microsatellite instability testing should be performed on sebaceous neoplasms to diagnose MTS as early as possible.

Sebaceous Carcinoma of the Eyelid

BACKGROUND

Periocular sebaceous carcinoma (PSC) is a rare but aggressive neoplasm that tends to clinically and histopathologically mimic other conditions. PSC can be challenging to diagnose using histomorphology alone given its overlap with 2 more common tumors that occur in this area (basal cell carcinoma [BCC] and squamous cell carcinoma [SCC]). Use of immunohistochemistry can help resolve this differential diagnosis.

METHODS

A review of the literature was performed, focusing on the epidemiology, morphology, and immunohistochemical features of PSC.

RESULTS

The most useful immunostains in the differential diagnosis of PSC are epithelial membrane antigen, Ber-Ep4, androgen receptor (AR), and adipophilin. To discern PSC from BCC, one should use EMA, Ber-Ep4, AR, and adipophilin, whereas discerning PSC from SCC can be achieved by evaluating AR and adipophilin. In addition, p53 and ERBB2 (formally known as HER2/neu) are other potentially useful immunohistochemical markers for the differential diagnosis of PSC.

CONCLUSIONS

Use of new immunohistochemical techniques, as well as the elucidation of molecular alterations, such as the presence of ERBB2 amplification, will advance our understanding of PSC.

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).

Adipophilin expression in cutaneous malignant melanoma

BACKGROUND

The lipogenic pathway is upregulated in cancer cells, including melanomas. However, the pathological significance of cellular lipids in melanocytic lesions has yet to be determined. In this study, we evaluated intracytoplasmic lipid droplets in melanocytic nevi (MNs) and malignant melanomas via immunohistochemical analysis of adipophilin (ADP), which coats lipid droplets.

METHODS

One hundred primary cutaneous melanocytic lesions [33 MNs, 17 melanomas in situ (MIS), and 50 invasive melanomas (IMs)] were immunostained for ADP. The intensity score (IS) and proportion score (PS) of ADP staining in each case was recorded semiquantitatively on a scale of 0 to 3+.

RESULTS

High ADP expression (IS2/3+ and PS2/3+) was observed in 27 primary cutaneous melanocytic lesions that consisted of 23 IMs, three MISs, and one MN. Consequently, high ADP expression was associated with malignancy (38.8% vs. 3.0%; p < 0.0001). Among the IMs, high ADP expression was more prevalent in pT3/4 than pT1/2 (63.3% vs. 23.8%; p = 0.01) and Stage 3/4 than Stage 1/2 (76.9% vs. 36.8%; p = 0.02).

CONCLUSIONS

The majority of the melanocytic lesions with high ADP expression were malignant melanomas in our cohort. Therefore, ADP expression may serve as a sensitive diagnostic marker for malignant melanoma.