Utility of YAP1 and NUT immunohistochemistry in the diagnosis of porocarcinoma.

BACKGROUND: Porocarcinoma is the malignant counterpart of poroma, a benign tumor derived from the eccrine or apocrine units. In contrast to poroma, porocarcinoma is rare and its diagnosis may be challenging. Recent work has identified YAP1-associated gene fusions in most poromas, and a subset of porocarcinomas. These included YAP1-MAML2 and YAP1-NUTM1, the latter being enriched in porocarcinomas over poromas. METHODS: We studied YAP1 C-terminus and NUT immunohistochemistry in a cohort of 12 porocarcinomas, 10 poromas, 10 squamous cell carcinomas, and 6 hidradenocarcinomas. RESULTS: Seven of 12 (58%) porocarcinomas showed loss of YAP1 C-terminus expression, consistent with a YAP1 fusion. Of these seven, five showed NUT positivity, implying the presence of the YAP1-NUTM1 fusion. One of 12 (8%) cases showed NUT positivity, but retention of YAP1 C-terminus expression, consistent with a non-YAP1 NUT-associated fusion. Eight of 10 (80%) poromas showed loss of YAP1 C-terminus expression and negative NUT staining, consistent with non-NUT YAP1 fusions. All squamous cell carcinomas and hidradenocarcinomas retained YAP1 C-terminus expression and were negative for NUT. CONCLUSION: YAP1 C-terminus and NUT immunohistochemistry may be helpful in the diagnosis of porocarcinoma, with the combination of YAP1 C-terminus loss and NUT positivity being particularly informative.

Metastatic porocarcinoma achieving complete radiological and clinical response with pembrolizumab.

A 67-year-old woman presented in 2012 with a crusty nodule on the left lower limb. Histopathological examination at this time reported a poorly differentiated squamous cell carcinoma (SCC). Two years later, she underwent lymphadenectomy and radiotherapy due to unilateral inguinal and pelvic sidewall nodal metastases. The following year she required excision of two subcutaneous lesions, reported pathologically to be SCC metastases. Further imaging following cyberknife radiotherapy to new brain metastases demonstrated widespread metastatic visceral disease. Twelve cycles of carboplatin and capecitabine failed to halt disease progression. In February 2017, she commenced pembrolizumab, achieving an excellent response and currently has no clinical or radiological evidence of disease. Given the unusual behaviour of her cancer, a histopathological review was requested. The diagnosis was revised to that of porocarcinoma (PC). This represents the first documented case of PC treated with immunotherapy. As of March 2019, the patient remains free of disease.

Recurrent Metastatic Eccrine Porocarcinoma: A Case Report and Review of the Literature.

BACKGROUND Eccrine porocarcinoma, or malignant eccrine poroma, is a rare primary skin tumor that develops in the sixth and seventh decades of life, and can present as a painless and solitary nodule. Histopathology is required to confirm the diagnosis. A rare case is presented of metastatic eccrine porocarcinoma, occurring four years after surgical excision of the primary scalp tumor, and includes a review of the literature. CASE REPORT A 67-year-old man initially presented with a scalp lesion that was non-painful, exophytic, and pigmented. Following complete excision, histopathology confirmed the diagnosis of eccrine porocarcinoma with clear resection margins. Four years later, he presented with discrete erythematous patches and plaques, in a zosteriform distribution, in the skin of the right neck, shoulder, and chest. A biopsy and histopathology of the skin rash confirmed metastatic eccrine porocarcinoma. A positron-emission tomography-computed tomography (PET-CT) scan identified areas of hypermetabolic activity, with a standardized uptake value (SUV) of 12, and an infiltrating soft tissue tumor in the right suboccipital region. Surgical resection of the suboccipital mass, followed by histopathology, confirmed metastatic eccrine porocarcinoma. During a postoperative ear, nose, and throat (ENT) examination, he was found to have metastases in the right ear canal. The patient received five cycles of chemotherapy, but later developed renal failure and eventually chose palliative care. CONCLUSIONS A rash-like presentation of skin metastasis to the trunk and metastasis to the ear from a primary eccrine porocarcinoma is rare. Early diagnosis and adequate surgical resection are recommended to reduce patient mortality.

Eccrine Porocarcinoma: Patient Characteristics, Clinical and Histopathologic Features, and Treatment in 7 Cases. / Porocarcinoma ecrino: aspectos demográficos, clínicos, histopatológicos y terapéuticos en una serie de 7 pacientes.

Eccrine porocarcinoma is a rare, malignant cutaneous adnexal tumor that arises from the ducts of sweat glands. Found mainly in patients of advanced age, this tumor has diverse clinical presentations. Histology confirms the diagnosis, detects features relevant to prognosis, and guides treatment. Growth is slow, but the prognosis is poor if the tumor metastasizes to lymph nodes or visceral organs. We report 7 cases of eccrine porocarcinoma, describing patient characteristics, the clinical and histopathologic features of the tumors, and treatments used. Our observations were similar to those of other published case series. Given the lack of therapeutic algorithms or protocols for this carcinoma, we propose a decision-making schema based on our review of the literature and our experience with this case series. The algorithm centers on sentinel lymph node biopsy and histologic features.

Detection of Merkel cell polyomavirus and human papillomavirus DNA in porocarcinoma.

BACKGROUND: Increasing evidences support the role of Merkel cell polyomavirus (MCPyV) and human papillomavirus (HPV) in non-cutaneous and cutaneous tumours. Porocarcinoma is a rare malignant neoplasm that arises from the intraepidermal ductal portion of the eccrine sweat glands. The aetiology of porocarcinoma is largely unknown and no systematic studies have been done to investigate the implication of infectious agents in the pathogenesis of this tumour. OBJECTIVES: To investigate the possible association between MCPyV and/or HPV infection and porocarcinoma. STUDY DESIGN: Forty-four formalin-fixed paraffin-embedded (FFPE) porocarcinomas (40 primary and 4 metastatic) and 10 healthy skin specimens (controls), were analysed for the presence of MCPyV and HPV DNA using molecular detection methods. RESULTS: MCPyV DNA was found in 27/40 (68%) primary porocarcinomas and in 3/10 (30%) controls (Fisher exact test: p<0.04). No significant difference in viral load was observed between tumours and healthy skin. Moreover, 2/40 primary porocarcinomas tested positive for high-risk HPV16. Cutaneous beta-HPV infection was detected in 16/40 (40%) porocarcinomas and in 6/10 (60%) controls. No particular beta-HPV types were significantly associated with tumour or with healthy skin. Two out of 4 metastatic biopsies were MCPyV DNA positive. All metastatic samples had mixed infections with cutaneous HPV types. CONCLUSIONS: This study demonstrated a significantly high prevalence of MCPyV and the presence of a broad spectrum of HPV types in porocarcinoma and provided the first available data about viral infections in this tumour. To understand the role, if any, of viral infections in the pathogenesis of porocarcinoma further studies are needed.

[Multiple recurrent eccrine porocarcinoma with inguinal metastasis. A case report]. / Porocarcinoma ecrino multirrecidivante con metástasis inguinal. Caso clínico.

BACKGROUND: Eccrine porocarcinoma, first described in 1963, is a rare malignant lesion arising from the eccrine sweat glands. It is usually a primary tumour, or even more common, a malignant degeneration of an eccrine poroma. It usually affects older persons and is located most commonly on the lower extremities. About 20% of eccrine porocarcinoma will recur after treatment. The treatment is wide local excision of the primary lesion. This uncommon skin tumour has a locally aggressive behaviour and a high recurrence rate. CLINICAL CASE: An 82 year-old man presenting with multiple recurrent eccrine porocarcinoma with inguinal metastasis. The treatment was a radical excision and inguinal lymphadenectomy. There were no postoperative complications, but there was local recurrence after six months. CONCLUSION: Early diagnosis and wide excision is the best way to achieve a good prognosis, due to the aggressiveness of this tumour.

Eccrine porocarcinoma with extensive cutaneous metastases.

BACKGROUND: Eccrine porocarcinoma (EPC) is an uncommon malignant neoplasm that originates in the intraepidermal portion of the eccrine sweat duct. Although porocarcinoma is a slow-growing tumor, up to 20% of cases can metastasize to regional lymph nodes, thus increasing mortality. METHODS: We describe the clinical and histopathological features and clinical course of three cases of extensive metastatic EPC diagnosed in our department over the last 10 years. RESULTS: All three patients were women aged 89-96 years. They had numerous skin tumors on the left leg that were histologically and immunohistochemically diagnosed as metastatic EPC. Only one patient had a history of primary porocarcinoma, which had been excised 6 years earlier. The remaining two patients had a previous lesion diagnosed as squamous cell carcinoma. We treated the patients with palliative radiotherapy and/or chemotherapy. Only one patient is currently alive. CONCLUSIONS: The cases of cutaneous and regional metastatic EPC we present occurred in elderly women with major involvement of the left leg. The third case is noteworthy, as the patient presented a long latency period before metastases appeared. Difficulties in the clinical diagnosis--and occasionally histological diagnosis--of primary EPC could delay more aggressive treatment, although optimal treatment does not always guarantee a good prognosis.

Eccrine Porocarcinoma Treated by Mohs Micrographic Surgery: Over 6-Year Follow-up of 12 Cases and Literature Review.

BACKGROUND: Eccrine porocarcinoma (EPC) has a poor prognosis after standard wide local excision (WLE), with 20% local recurrence, 20% regional and 12% distant metastatic rates. Mohs micrographic surgery (MMS) has been used as a promising treatment. OBJECTIVE: To review the use of MMS for EPC and assess treatment outcomes. MATERIALS AND METHODS: This was a retrospective case series of 12 EPC patients treated by MMS between 1984 and 2013 in the institution. Furthermore, a literature review revealed an additional 17 cases of EPC managed by MMS. RESULTS: Of 29 cases of EPC treated by MMS, outcome was established in 27 cases. The patients had a significantly longer mean follow-up period of 6 years (range, 4-206 months), as compared with 19 months (range, 2-48 months) in reported cases. Two patients had regional lymph node metastasis after MMS. The regional metastatic rates to lymph nodes were 7% (2/27). There was no local recurrence, distant metastasis, or disease-specific death in the 27 cases studied. CONCLUSION: To the best of the authors' knowledge, this is the single largest case series of EPCs treated by MMS and the authors' data demonstrated that MMS may be superior to the standard WLE.

Eccrine porocarcinoma with carcinomatous lymphangitis in a patient with history of arsenic exposure: a case report.

Eccrine porocarcinoma is a potentially fatal form of sweat gland carcinoma, due to its propensity to metastasize through lymph vessels. The authors report the case of a 69-year-old female who presented with swelling of the right leg and an ulcerated lesion of the right great toe. The initial histologic diagnosis was invasive squamous cell carcinoma. On follow-up, the patient developed lymphangitic tumor spread in the right leg, associated with right inguinal lymphadenopathy and lesions in vulva and flank. Reevaluation of the toe lesion led to a revised diagnosis of eccrine porocarcinoma. The patient also had 2 basal cell carcinomas of the multicentric/superficial type in the skin overlying the left breast. Past history included chronic ingestion of liquore arsenic (Fowler's solution) in early adulthood as treatment for dermatitis herpetiformis.

A case of porocarcinoma arising in pigmented hidroacanthoma simplex with multiple lymph node, liver and bone metastases.

Porocarcinoma is a rare skin appendage carcinoma that may arise de novo or be associated with pre-existing poroma and hidroacanthoma simplex (HAS). Here, we report a case of porocarcinoma arising in pigmented HAS, which led to death from multiple lymph node, liver and bone metastases. A 72-year-old Japanese man presented with a brown to focal black flat plaque, measuring 17 × 12 mm, on the posterior region of his right thigh. Histopathological study of the tumor revealed that there was intraepidermal proliferation of small-sized basaloid cells, and it exhibited the 'Jadassohn phenomenon', with dendritic melanocytes, and a few ductal structures were observed. Continuing to the intraepidermal nests, the invasive proliferation of large polygonal cells with occasional intracytoplasmic ductal structures was observed. Carcinoembryonic antigen and epithelial membrane antigen were expressed in some carcinoma cells and they highlighted the intracytoplasmic ductal structures. Multiple lymph node, liver and bone metastases were observed, and the patient died 8 months after the initial surgery. Clinical diagnosis of HAS is extremely rare. Porocarcinoma may be associated with pre-existing HAS and sometimes shows aggressive behavior. Therefore, pigmented HAS must be included in the differential diagnosis of brown or black lesions. Ishida M, Hotta M, Kushima R, Okabe H. A case of porocarcinoma arising in pigmented hidroacanthoma simplex with multiple lymph node, liver and bone metastases.