Successful Treatment of Metastatic Primary Cutaneous Adnexal Carcinoma With a PD-1 Inhibitor.

SUMMARY: Standard of care treatment for metastatic cutaneous adnexal carcinomas is not well established. In this case report, we highlight the successful use of anti-programmed cell death protein 1 (anti-PD-1) therapy in treating a patient with low tumor mutation burden, microsatellite stable, high programmed death-ligand 1 (PD-L1) gene expression, metastatic primary cutaneous adnexal carcinoma with significant radiographic, and circulating tumor DNA response with durable benefit. Immune checkpoint inhibitors hold promise as a future treatment option in rare instances of metastatic disease from primary skin adnexal carcinoma. Further studies are needed to identify better immune checkpoint inhibitor predictive biomarkers for rare, advanced-stage non-melanoma skin cancers.

Nectin-4 expression in a subset of cutaneous adnexal carcinomas: A potential target for therapy with enfortumab vedotin.

BACKGROUND: Enfortumab vedotin (EV) is an antibody-drug conjugate directed against Nectin-4 that is used to treat urothelial carcinoma. Nectin-4 is inherently expressed in the skin and adnexal structures. Since therapeutic options for cutaneous adnexal carcinomas are limited, we sought to evaluate Nectin-4 expression in adnexal carcinomas and benign adnexal neoplasms to identify tumors that are potentially targetable with EV. METHODS: Eight sebaceous carcinomas (seven periocular and one lymph node metastasis), eight digital papillary adenocarcinomas, seven squamoid eccrine ductal carcinomas, eight poromas, eight trichilemmomas, and seven sebaceous adenomas were subjected to immunohistochemical staining for anti-Nectin-4 antibody. H-scores for Nectin-4 expression were calculated. RESULTS: Benign adnexal neoplasms had a significantly lower mean (±SD) Nectin-4 H-score (142.6 ± 39.1) than did the adnexal carcinomas (198 ± 90.8; p = 0.006). Nectin-4 was expressed in 91% (21/23) of adnexal carcinomas. Sebaceous carcinomas frequently exhibited high expression of Nectin-4 (88% [7/8]), with a mean (±SD) H-score (258.1 ± 58.4) significantly higher than those for digital papillary adenocarcinomas (197.5 ± 52.5; p = 0.035) and squamoid eccrine ductal carcinomas (131.4 ± 114.1; p = 0.031). Sebaceous carcinomas also had significantly higher H-scores than did sebaceous adenomas (186.4 ± 25.0; p = 0.013). CONCLUSIONS: Increased Nectin-4 expression in a subset of cutaneous adnexal carcinomas, particularly sebaceous carcinomas, reveals that EV is a potential therapeutic option for these tumors.

The assessment of tumor-infiltrating lymphocytes in invasive apocrine carcinoma of the breast in relation to the HER2 status.

In the current study, we assessed the prevalence and molecular features of HER2-low phenotype in the apocrine carcinomas of the breast (ApoCa) and its relationship with tumor-infiltrating lymphocytes (TILs). A cohort of 64 well-characterized therapy-naïve ApoCa was used. The TIL distribution was assessed using the hematoxylin and eosin whole slide/scanned images following the international TILs working group recommendations. Next-generation sequencing (NGS) was performed in a subset of HER2-low ApoCa. All patients were women, with a mean age of 62 years. Forty-three carcinomas were pure apocrine carcinoma (PAC; ER-/AR+), and the remaining 21 were classified as apocrine-like carcinomas (ALCs; ER+/-, AR+/-). HER2/neu was positive (score 3+ by IHC and/or amplified by FISH) in 20/43 (47%) PAC and 4/21 (19%) ALC. The prevalence of HER2-low expression (scores 1+ or 2+ without HER2 amplification) in ApoCa was 39% without significant differences between PAC and ALC (P = 0.14); however, the HER2-low phenotype was more prevalent in triple-negative PAC than in ALC (P < 0.001). Levels of TILs were low (≤10%) in 74% of ApoCa (median 5%, range 0%-50%). TIL levels were significantly higher in ALC than in PAC (P = 0.02). HER2 status had no impact on TIL distribution (P = 0.45). The genomic profile of HER2-low ApoCa was similar to other subtypes of ApoCa. ApoCa has predominantly low TIL, particularly PAC. The prevalence of the HER2-low phenotype in ApoCa is high, which should have therapeutic and clinical implications given the recently approved therapies with antibody-drug conjugates (ADCs) for HER2-low breast cancers.

Apocrine carcinoma with marked sebocyte-like cytological features: A report of two cases.

Apocrine carcinoma cases with sebaceous differentiation have not been reported and can be misdiagnosed as sebaceous carcinoma. We present two cases of apocrine carcinoma with marked sebocyte-like cytological features. Tumors were observed in the left axilla of a 68-year-old man (Case 1) and the right axilla of a 72-year-old man (Case 2). Both patients presented with multiple lymph node metastases. Histopathology revealed densely distributed solid nests of tumor cells containing foamy cytoplasm and enlarged round nuclei with prominent nucleoli. The tumor cells diffusely expressed adipophilin, PRAME (cytoplasmic pattern), androgen receptor, BerEP4, and GCDFP15 but did not express p63 in both cases. PIK3CA E726K and H1047R mutations were detected in Cases 1 and 2, respectively. Tumor location in the axilla, the presence of eosinophilic granular cytoplasm, prominent nucleoli, and PIK3CA mutations, immunoreactivity for BerEP4 and GCDFP15, and lack of p63 immunoexpression findings matched apocrine carcinoma characteristics, but not sebaceous carcinoma. Thus, apocrine carcinoma can demonstrate intracytoplasmic lipid accumulation and rarely exhibit sebocyte-like cytological features. Apocrine carcinoma should be distinguished from sebaceous carcinoma due to the former's higher metastatic potential and lack of association with Muir-Torre syndrome.

Endocrine Mucin-Producing Sweat Gland Carcinoma and Primary Cutaneous Mucinous Carcinoma: A Case Series.

Endocrine mucin-producing sweat gland carcinoma (EMPSGC) and primary cutaneous mucinous carcinoma (PCMC) are rare low-grade neoplasms thought to arise from apocrine glands that share many histological features and are proposed to be on a single histopathologic continuum, with EMPSGC as the in situ form that may progress to the invasive PCMC. Management involves a metastatic workup and either wide local excision (WLE) with greater than 5 mm margins or Mohs micrographic surgery (MMS) in anatomically sensitive areas. We present 2 cases of EMPSGC and 3 cases of PCMC and review their clinical and histopathologic features, differential diagnoses, and treatment.

A Case of Biphenotypic Adnexal Carcinoma With Bowenoid and Basaloid Features: Focus on the Expression of SOX9 and Wnt Signaling Pathway Molecules, Including CDX2.

ABSTRACT: An 87-year-old woman presented with a pedunculated nodule of 1.2 × 1.2 × 0.6 cm on her left cheek. Microscopic examination of the lesion revealed bowenoid and rosette-like basaloid components, resembling Bowen disease and neuroendocrine carcinoma, respectively. Immunohistochemically, both components were positive for Wnt signaling pathway molecules-nuclear/cytoplasmic beta-catenin, lymphoid enhancer binding factor 1 (LEF1), and caudal type homeobox 2 (CDX2)-and the adnexal marker SRY-box transcription factor 9 (SOX9). Unlike neuroendocrine tumors and basal cell carcinomas, the basaloid component in the present case was negative for chromogranin A, INSM1, synaptophysin, and p40. Previously reported cases of similar CDX2-positive lesions were diagnosed as squamous cell carcinoma with enteric adenocarcinomatous differentiation and basaloid cutaneous carcinoma with a primitive cytomorphology. However, the lesion in the present case was simultaneously positive for SOX9, indicating adnexal differentiation. In particular, the expression of multiple Wnt signaling pathway molecules indicates follicular differentiation despite the absence of morphological follicular features, such as shadow cells. Moreover, shared immunopositivity for SOX9, CDX2, nuclear/cytoplasmic beta-catenin, and LEF1 by both bowenoid and basaloid components indicated that the bowenoid component did not represent Bowen disease but a part of the adnexal tumor, and that the basaloid component was not a tumor-to-tumor metastasis. After complete excision, no recurrence has been observed for 5 months. The findings of the present case expand the histological spectrum of cutaneous adnexal tumors with follicular immunophenotypic differentiation.

Metastatic hidradenocarcinoma: a report of two rare cases.

BACKGROUND: Hidradenocarcinoma is a rare malignant sweat gland tumour, characterized by a slow but aggressive course, with high rates of local recurrence and metastasis. Due to its rarity, histological criteria and therapeutic guidelines are poorly defined, posing a major challenge for clinicians and pathologists. OBJECTIVES: To present two new cases of metastatic hidradenocarcinoma as well as a review of the literature. MATERIALS & METHODS: We describe two case studies and a review of the literature based on a search using the MEDLINE (PubMed) electronic database. RESULTS: The first patient was a 61-year-old woman with a perimamillary hidradenocarcinoma that arose from the malignant transformation of a benign childhood lesion and developed regional lymph node metastases after wide excision and adjuvant radiotherapy. The second patient was a 63-year-old man who developed cutaneous and renal metastases several years after the complete excision of a lumbar hidradenocarcinoma. As far as we can ascertain, kidney metastasis from hidradenocarcinoma has not previously been described. CONCLUSION: Most authors recommend wide excision as the treatment of choice for hidradenocarcinoma, however, optimal adjuvant therapy remains to be determined. Our cases add to the limited knowledge available, but high-quality studies to find new effective treatments are needed.

Whole-Exome Sequencing of a Case of Squamoid Eccrine Ductal Carcinoma Reveal Similarities With Cutaneous Squamous Cell Carcinoma.

ABSTRACT: Squamoid eccrine ductal carcinoma (SEDC) is a poorly documented but likely underrecognized sweat gland malignancy with significant risk for local recurrence and potential for metastasis and rare disease-related mortality. Histopathologically, the tumor demonstrates a biphasic differentiation pattern: superficially, the tumor has squamous differentiation [indistinguishable from well-differentiated cutaneous squamous cell carcinoma (cSCC)], while the deeper aspect has a more infiltrative pattern with prominent ductal differentiation. Diagnosis of SEDC relies upon histopathologic examination alone. Its pathogenesis is poorly understood, and its genomic features have yet to be described. In this article, we characterize the genomic features in a case of SEDC through whole-exome sequencing, then compare its features with cSCC and other eccrine ductal carcinomas. Whole-exome sequencing revealed 30 mutations/Mb with 21 pathogenic or likely pathogenic mutations in total, identified across 14 different genes. The genomic abnormalities identified in this case of SEDC overlap considerably with those found in cSCC but not those of other sweat gland malignancies. The clinical and histopathologic features of SEDC previously reported and the genetic features determined from this case suggest that this tumor may arise initially as a well-differentiated cSCC that subsequently undergoes divergent differentiation focally to resemble a sweat gland malignancy. Genetic analyses of additional cases are warranted to clarify this consideration.

Low-Grade Hidradenocarcinoma of the Foot With Metastasis to a Lymph Node.

ABSTRACT: Hidradenocarcinoma (HAC) is a rare adnexal tumor associated with the potential for locoregional recurrence and systemic metastasis. The clinical appearance of HAC is nonspecific, frequently presenting as a solitary firm subcutaneous nodule or plaque on the head and neck region or distal extremities. These tumors show histomorphologic heterogeneity, as they can be low and high grade. Distinguishing HAC from hidradenoma, especially the low-grade variant of HAC, can be challenging as both tumors can show histologic overlapping features. In this article, we describe a case of a 33-year-old patient presenting with a low-grade HAC of the plantar foot who was subsequently found to have lymph node metastasis.

Two distinct pathogenic pathways of digital papillary adenocarcinoma - BRAF mutation or low-risk HPV infection.

Digital papillary adenocarcinoma (DPA) is a rare neoplasm that can exhibit local recurrence and distant metastasis. We present a series of eight cases of DPA showing two distinct clinical presentations, morphologies, immunophenotypes, and molecular features. Four cases were characterized by painless, slow-growing nodules located on the digits. The lesions were small, well-defined, and confined in the dermis. Histopathologically, these tumors were composed of glandular structures lined by cuboidal epithelium with luminal papillary infoldings. Only rare mitotic figures and minimal squamoid differentiation were present, and cellular necrosis was absent. All four cases were positive for the BRAF V600E immunohistochemistry but negative for p16, low-risk and high-risk HPV in situ hybridization (ISH). In contrast, the remaining four cases were characterized by painful, rapidly growing masses on the digits. These four lesions were located in the deep dermis and consisted of a solid, tightly packed papillary architecture lined by atypical epithelioid cells with inconspicuous nucleoli. Cellular necrosis, numerous mitotic figures, and prominent squamoid differentiation were seen. All cases were negative for the BRAF V600E IHC. However, they showed strong, patchy to diffuse reactivity for p16 and were positive for low-risk HPV ISH and negative for high-risk HPV ISH. Our findings suggest that the current classification of DPA encompasses tumors that show two discrete pathogenic pathways - BRAF mutation or low-risk HPV infection. DPAs with low-risk HPV infection exhibit aggressive clinical features, high-grade morphology, marked squamoid differentiation, and wild-type BRAF. DPAs with BRAF V600E have less aggressive clinical features, low-grade morphologic findings, mild to absent squamoid differentiation, and negative HPV infection.

Microsecretory adenocarcinoma of the skin, a novel type of sweat gland carcinoma: Report of three additional cases.

Microsecretory adenocarcinoma (MSA) is a newly described salivary gland tumor harboring a characteristic balanced chromosomal translocation resulting in MEF2C::SS18 gene fusion. Six primary cutaneous MSA cases have been recently described. We report three additional cases confirming the relevance of this recently identified entity of primary cutaneous adnexal tumor. Three patients aged 53-, 64- and 78-year-old were retrospectively diagnosed with MSA of the skin (MSAS) as consultation cases of the CARADERM (CAncers RAres DERMatologiques) national network. The clinical presentation was an indolent nodule on the upper extremities. There was no history of salivary gland tumor. Histopathologically, the tumors presented as dermal nodular proliferation with slightly infiltrative borders, composed of cribriform and microcystic structures with abundant myxoid intraluminal secretion embedded in a fibromyxoid stroma. They diffusely expressed cytokeratin 8 and SOX10, focally p63 and heterogeneously smooth muscle actin. All tumors harbored the MEF2C::SS18 gene fusion. A complete surgical excision was performed. No local recurrence or distant metastases were observed so far (follow-up: 17, 38, and 45 months). MSAS is the cutaneous homologue of MSA of the salivary gland, a low-grade adnexal neoplasm whose prognosis seems to be excellent once the complete removal of the tumor is assured.

Distant metastasis from morphologically low-grade spiradenocarcinoma: A report of two cases.

Malignant tumors arising from benign eccrine spiradenomas are rare. They are divided by morphology into low-grade and high-grade spiradenocarcinomas, with prognosis and metastatic potential closely linked to their histopathologic features. Tumors with low-grade morphology are known for their indolent behavior, with only two reported instances of metastatic spread. We report herein two further low-grade metastatic spiradenocarcinomas resulting in distant metastasis. Both tumors showed a background of a benign spiradenoma and subtle histopathologic signs of malignant transformation, characterized by loss of the dual-cell population, up to moderate cytological atypia and increased mitotic activity. Both patients developed metastases to the lungs years after the initial presentation, and one showed additional lymph nodal disease. We show that even the morphologically low-grade tumors may rarely show more aggressive behavior. Although often challenging, recognition of the morphologically low-grade malignant spiradenocarcinoma and long-term follow-up of the patients are important to detect metastatic disease.

Value of Immunohistochemistry to Differentiate Digital Papillary Adenocarcinoma From Acral Hidradenoma With Papillary Structures.

ABSTRACT: Digital papillary adenocarcinoma is a malignant adnexal tumor with a predilection for acral sites. Hidradenoma is a benign solid and cystic sweat gland neoplasm with focal ductal and glandular differentiation and good outcomes. Hidradenomas can occur at acral sites and show papillary structures; for this reason, they are included in the differential diagnosis of digital papillary adenocarcinoma, and immunohistochemistry is a valuable tool in this scenario. We described a case of a 43-year-old man with an epithelial tumor showing papillary structures in the intermediate phalanx of the fourth finger. There was diffuse positivity for p63 and negativity for S100 protein, suggesting that this tumor was an acral hidradenoma with papillary structures.

Sweat Gland Carcinoma With Neuroendocrine Differentiation of the Areola as a Potential Clinicopathologic Mimicker of Male Breast Carcinoma and Syringocystadenocarcinoma Papilliferum.

ABSTRACT: Sweat gland carcinoma with neuroendocrine differentiation (SCAND) is a newly proposed tumor entity of primary cutaneous apocrine/eccrine adnexal tumor with neuroendocrine differentiation. The histopathologic variations are not yet well known. In this article, we present a case of SCAND mimicking male breast cancer and syringocystadenocarcinoma papilliferum. A 68-year-old man presented with a reddish 12-mm nodule on his left areola. No lymph node or distant metastases were observed. The patient was disease free 1 year and 9 months after the tumor was surgically resected but died of cerebral hemorrhage. Histopathological examination revealed a predominantly intradermal tumor with marked syringotropism, mimicking a component of mammary ductal carcinoma in situ. In addition, another tissue section displayed a cup-shaped papillated tumor with syringocystadenocarcinoma papilliferum-like features, which were also seen because of marked syringotropism. Diffuse immunoexpression of cytokeratin 7, cytokeratin 19, chromogranin A, synaptophysin, INSM1, estrogen receptor, carcinoembryonic antigen, epithelial membrane antigen, and GATA3 was observed in the tumor, but no BRAF immunoexpression was seen. The present case would help us to understand the histopathological variation and differential diagnosis of SCAND. The histopathological diagnosis of male breast cancer or syringocystadenocarcinoma papilliferum should be made by ruling out SCAND.

[Unusual localisation of rare primary skin carcinoma: a case report]. / Une localisation inhabituelle d'un carcinome primitif cutané rare: à propos d'un cas.

Adnexal carcinomas are rare, accounting for less than 1% of skin carcinomas. Sclerosus carcinoma of the sweat glands was first described by Goldstein et al. in 1982. We here report the case of a 33-year-old female patient with a retracted perianal skin lesion. Histological examination of perilesional skin biopsy, immunohistochemistry, and negative results of laboratory tests, radiological and endoscopic investigations allowed for the diagnosis of eccrine sclerosus carcinoma. This is a rare tumor, usually characterized by facial localization and slow but aggressive progression. It poses problems in differential diagnosis with benign and malignant tumors; hence the challenge encountered by pathologist of suspecting this carcinoma in patients with any sclerotic and infiltrating skin lesion characterized by slow progression, in a context of preservation of the general state and in the absence of neoplastic history as well as of feeling free to ask for new deep biopsies when in doubt.