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.

[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.

NECTIN4 expression in sebaceous and sweat gland carcinoma

Background: Sebaceous carcinoma and sweat gland carcinoma (malignant tumours with apocrine and eccrine differentiation) are rare malignant adnexal tumours that differentiate toward sebaceous glands and eccrine and apocrine glands, respectively. Because of the rarity of these malignancies, standard treatments for advanced disease have yet to be established. The outcomes of patients with systemic metastasis remain poor, highlighting the need for novel treatment strategies. Nectin cell adhesion molecule 4 (NECTIN4) and its antibody-drug conjugate, enfortumab vedotin, have attracted attention as potential treatments for solid tumours. Objectives: To examine the potential use of NECTIN4-target therapy for sebaceous and sweat gland carcinoma. Materials & Methods: We immunohistochemically investigated NECTIN4 expression in 14 sebaceous carcinoma samples and 18 sweat gland carcinoma samples, and examined whether NECTIN4-targeted therapy could be applied to these cancers. Results: We found strong and frequent expression of NECTIN4 in both cancers. All tumours exhibited positive staining at least in a part of the lesion, and the mean H-score, a semiquantitative score ranging from 0 to 300, was 259.4 for sebaceous carcinoma and 253.1 for sweat gland carcinoma. Conclusion: Our results suggest that both sebaceous carcinoma and sweat gland carcinoma could be potentially treated with NECTIN4-targeted antibody-drug conjugates, such as enfortumab vedotin.

CDX2 and SATB2 positivity in pilomatrix carcinoma: Avoiding an erroneous diagnosis of cutaneous metastasis of gastrointestinal origin.

An 80-year-old female presented with a slowly growing 2-cm nodule on her shoulder over a 1-year period. Histopathologic sections of a biopsy specimen showed a multinodular, dermal-based basaloid tumor with areas of clear-cell change, stromal induction, as well as significant cytologic atypia and atypical mitotic activity. An initial investigation revealed positive staining of CDX2, a well-known marker of tumors of gastrointestinal origin. The case was referred to our dermatopathology service for consultation to determine if the lesion was in keeping with a cutaneous metastasis. On receipt of the case, an extended immunohistochemical panel was performed including SATB2, which displayed a similar pattern of staining as seen with CDX2. Although pathologists are most familiar with CDX2 and SATB2 as markers of gastrointestinal origin, the recent dermatopathology literature highlights that primary adnexal lesions of the skin also display positivity for CDX2 and can exhibit SATB2 positivity. We share a case of pilomatrix carcinoma with positive expression of nuclear CDX2 and SATB2, adding to the recent literature to (a) increase recognition of this staining pattern in hair follicle tumors, and (b) discuss briefly the shared molecular underpinnings in the tumorigenesis of gastrointestinal tumors and tumors of hair follicle origin that help clarify this underrecognized immunohistochemical pattern.

Skin adnexal carcinoma with BRD3-NUTM2B fusion.

NUT carcinomas are genetically defined epithelial neoplasms. Most tumors harbor fusions of NUTM1 with BRD4 or BRD3. Their histopathologic features have been predominantly reported as undifferentiated or poorly differentiated squamous cell carcinoma, and clinically they tend to be aggressive cancers. However, recent studies have revealed a broader spectrum of NUTM1-rearranged neoplasms with several new fusion partners and associated variable histopathologic phenotypes and clinical behaviors, including benign and malignant cutaneous poroid tumors. We report herein a primary invasive carcinoma of skin adnexal origin with a previously undescribed fusion between BRD3 and NUTM2B. The tumor occurred on the shoulder of a 7-year-old girl and was excised with negative margins. A sentinel lymph node was positive. After follow-up of 23 months, and without systemic treatment, the child remains free of tumor. This case expands the spectrum of NUT carcinomas by including a skin adnexal variant with follicular infundibular differentiation, a novel genomic aberration, and preliminary evidence of a less aggressive clinical course.

Independent primary cutaneous and mammary apocrine carcinomas with neuroendocrine differentiation: Report of a case and literature review.

Cutaneous apocrine carcinomas share common features with their counterparts in the breast; hence, metastatic mammary carcinoma must be excluded before such lesions can be designated primary cutaneous neoplasms. Primary tumors from either source rarely exhibit neuroendocrine differentiation. We report a case of a 72-year-old female with a painless 1.2-cm scalp nodule. An incisional biopsy revealed dermal involvement by an invasive apocrine carcinoma juxtaposed to a benign apocrine cystic lesion. Immunohistochemically, the carcinoma expressed neuroendocrine proteins including synaptophysin, chromogranin, and CD56. A primary cutaneous apocrine carcinoma with neuroendocrine differentiation was favored, but additional investigations to exclude breast origin were recommended. These revealed a 1.1-cm nodule in the right breast, which proved to be an invasive ductal carcinoma, morphologically and immunophenotypically similar to the scalp lesion. This confounded the case, yet factors militating against metastatic breast carcinoma to skin included (a) the small size of the mammary tumor, (b) absence of other metastatic disease, and (c) juxtaposition of the scalp carcinoma to a putative benign precursor. Molecular studies were undertaken to resolve the diagnostic quandary. Single nucleotide polymorphism microarray analysis revealed distinct patterns of chromosomal copy number alterations in the two tumors, supporting the concept of synchronous and unusual primary neoplasms.

Vulvar apocrine hidradenocarcinoma arising in a hidradenoma papilliferum-A case report.

Hidradenoma papilliferum (HP) is a benign adnexal neoplasm of the vulva that typically presents as a unilateral, flesh-colored papule in the labium majus in middle-aged Caucasian women. It is considered to be a close counterpart of the intraductal papilloma of the breast. Malignant transformation is rare with few reports in the literature. We present a case of vulvar mammary-type apocrine hidradenocarcinoma arising in an HP.

A clinical, pathological and immunohistochemical series of 9 cases of primary cutaneous apocrine carcinomas of the head and neck.

BACKGROUND/OBJECTIVES: Primary cutaneous apocrine carcinoma is a rare malignant adnexal skin tumour that can recur locally, spread to regional lymph nodes and metastatize to visceral organs. Wide dissemination and death from disease are much less common. The axilla is the most common site of presentation. It is infrequently reported in the head and neck region. METHODS: All cases diagnosed as primary cutaneous apocrine carcinoma of the head and neck were retrospectively collected from the archives of the Division of Pathological Anatomy, University of Florence from 1996 to 2016. There was no history or clinical evidence of breast cancer. Clinical data and follow-up were collected by the clinicians. RESULTS: Nine cases were found, with a mean age of 76 years, ranging in size between 0.3 and 3.5 cm. Clinically, they were frequently mistaken for basal cell carcinomas. Histopathologically, all the tumours showed decapitation secretion, a tubular, solid or mixed (tubulo-papillary and solid-tubular) growth pattern and were predominantly classified as grade 2 tumours. GCDFP-15 and hormone receptors were variably expressed. HER2 and podoplanin were negative in all cases. In one case, spreading to regional lymph nodes was observed. No cases were associated with death due to the disease. CONCLUSION: As immunohistochemical analysis lacks specificity in distinguishing primary cutaneous apocrine carcinoma from a cutaneous metastasis of breast carcinoma, detailed clinical history, breast examination, adequate treatment and follow-up are necessary to confirm a diagnosis of primary cutaneous apocrine carcinoma.

Pápula solitaria nasal de larga evolución / Long-Standing Solitary Nasal Papule

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Matrical carcinoma with melanocytic hyperplasia mimicking nodular melanoma in an elderly Mexican male.

Matrical carcinoma with melanocytic hyperplasia (MCMH), previously referred to as malignant melanocytic matricoma, is a rare variant of the uncommon pilomatrical carcinoma, occurring most often on the head/neck and upper backs of middle-aged men. Nodular lesions may resemble pigmented basal cell carcinoma or melanoma clinically. We present a case of MCMH in a Hispanic patient with history of melanoma. Histopathological clues to appropriate diagnosis include basaloid cells, numerous atypical mitotic figures, matrical differentiation, shadow cells, strong diffuse nuclear and cytoplasmic expression of ß-catenin, and interspersed pigmented dendritic melanocytes.