Periungual eccrine porocarcinoma

Primary Eccrine Porocarcinoma of the Thumb With Metastasis: A Rare Case Report and Literature Review

ABSTRACT

Eccrine porocarcinoma (EPC) is a rare malignant sweat gland tumor that accounts for approximately 0.005% of all cutaneous carcinomas. It favors the lower extremities. Only 3% of EPCs are on the hand, and only 6 cases occurring specifically on fingers have been previously documented. However, we met a patient with EPC presenting the primary lesion on the left thumb and an extensive cutaneous metastasis on the left forearm. Pathologic findings of axillary lymph nodes confirmed lymphatic metastasis.

A systematic review of periungual eccrine neoplasms

Eccrine tumors are a rare cutaneous adnexal neoplasm originating from the sweat glands. The periungual region represents an uncommon localization for these neoplasms. We analyzed all published demographic, clinical, and treatment data on periungual eccrine tumors. A systematic review following PRISMA guidelines was performed of articles published prior to March 2021. Articles were included in the review if a full-text English version was available. Of the surveyed literature, 27 full-text case reports were included in the final analysis. Benign eccrine poroma and porocarcinoma were the most common tumor subtypes (nine and eight cases, respectively). Males were only affected by poroma and porocarcinoma, while females were affected by all tumor subtypes. The first toe was the most common lower extremity affected. Misdiagnosis led to delayed treatment in 25% of cases. As such, while periungual eccrine neoplasms are rare diagnoses, the nonspecific presentations of these growths raise concerns about misdiagnosis and delayed treatment. Further research is needed related to sex-differences in the epidemiology of these growths and into the prevalence of the first toe as a location. These tumors should be considered in the differential diagnosis for nail unit afflictions.

[Malignant nail tumors]

Because of the large number of different tissues making up the distal phalanx of fingers and toes, a large variety of malignant tumors can be found in and around the nail apparatus. Bowen disease is probably the most frequent nail malignancy. It is usually seen as a verrucous plaque of the nail fold and nail bed in persons above the age of 40 years. It slowly grows over a period of years or even decades before degenerating to an invasive squamous cell carcinoma. The latter may also occur primarily often as a weeping onycholysis. The next most frequent nail malignancy is ungual melanoma. Those arising from the matrix are usually pigmented and often start with a longitudinal melanonychia whereas those originating from the nail bed remain amelanotic, are often nodular and mistaken for an ingrown nail in an elderly person. The treatment of choice for in situ and early invasive subungual melanomas is generous extirpation of the nail apparatus whereas distal amputation is only indicated for advanced melanomas. In addition to these frequent nail malignancies, nail-specific carcinomas, malignant vascular and osseous tumors, other sarcomas, nail involvement in malignant systemic disorders and metastases may occur. In most cases, they cannot be diagnosed accurately on clinical grounds. Therefore, a high degree of suspicion is necessary in all isolated or single-digit proliferations that do not respond to conservative treatment.

Primary eccrine porocarcinoma of the finger with transit forearm and axillary metastasis

Sweat gland tumors of the upper extremity are uncommon. Eccrine porocarcinoma is a rare skin malignant lesion representing 0.005% to 0.01% of all cutaneous tumors, which most commonly presents in patients more than 60 years of age. Approximately 250 cases of eccrine porocarcinoma have been reported since this disease was first described in 1963. However, only 2 cases occurring specifically on the finger (including the current case) have been documented in the literature to date. On the basis of the rarity of eccrine porocarcinoma of the finger, we report an eccrine porocarcinoma that presented as an ulcerated lesion of the left ring finger with metastasis to the forearm and axilla in an 80-year-old man. The etiology, diagnosis, treatment, and prognosis of this disease are discussed, with a brief review of the literature.

Eccrine porocarcinoma (malignant eccrine poroma): a clinicopathologic study of 69 cases

The clinicopathologic characteristics of 69 cases of eccrine porocarcinoma (EP) have been studied. Seven cases of purely in situ disease are included. Forty patients were female, 29 male with ages ranging from 29 to 91 years (mean 73 years). The lower extremity represented the single most common site (44%). Other common sites were the trunk (15 cases, 24%) and head (11 cases, 18%). The histologic diagnosis of EP was predicated on the basis of an irregular tumor at least partly formed of characteristic poromatous basaloid epithelial cells displaying ductal differentiation, and significant cytologic atypia. Forty-seven tumors (68%) contained mature well-formed eccrine ducts having an eosinophilic luminal cuticle, with the remaining tumors containing small ill-formed ducts and/or intracytoplasmic lumina. All ducts were discernible via light microscopy and in 49 cases were highlighted with DPAS stain and/or CEA/EMA immunocytochemistry. A variant with a broad pushing tumor margin and marked nuclear pleomorphism showed some resemblance to proliferative bowenoid dysplasia. In 11 cases (18%) the tumors appeared to arise in continuity with a benign preexistent poroma. A variety of histologic patterns were displayed including clear, squamous, and spindle cell differentiation, mucus cell metaplasia, and colonization by melanocytes. Lymphovascular invasion was present in 9 cases (15%). Three cases showed pagetoid extension of malignant cells (epidermotropism) and appeared to be multifocal. Follow-up was available in 54 patients (78%) with 9 (17%) experiencing local recurrence, 10 developing lymph node metastases (19%), and 6 (11%) experiencing distant metastases or death. Mitoses, the presence of lymphovascular invasion, and tumor depth >7 mm were associated with a poorer prognosis. Dividing tumors into those with a "pushing" or "infiltrating" advancing margin was also predictive of outcome with the latter having an increased risk of local recurrence. This report, the largest series of EP to date, suggests that the incidence of aggressive behavior is less than popularly believed. Furthermore, EP can display a wide variety of histologic patterns that may lead to diagnostic error in the unwary. The large number of cases in this series enables a reliable evaluation of prognostic parameters. A more aggressive clinical course may be indicated by more than 14 mitoses per high power field (hazard ratio [HR] for death 17.0, 95% confidence interval [CI] 2.71-107), lymphovascular invasion by tumor (HR 4.41, CI 1.13-17.2), and depth >7 mm (HR 5.49, CI 1.0-30.3). Thus, mitoses, lymphovascular invasion, and tumor depth should be evaluated in these tumors. We also suggest that tumors presenting an "infiltrative" advancing margin are particularly prone to local recurrence and require wide excision with close attention to the surgical margins by the reporting pathologist.

Malignant eccrine poroma of the hand

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Metastasizing eccrine porocarcinoma: report of a case and review of the literature

Eccrine porocarcinoma is a rare malignant tumor arising from the intraepidermal ductal portion of the eccrine sweat gland (acrosyringium). It usually affects older persons and is located most commonly on the lower extremities. We describe a 55-year-old man with an aggressive metastasizing eccrine porocarcinoma diagnosed 10 years after the primary lesion. The metastatic lesions were located in the public area and scrotum and were associated with progressive lymphedema. Several biopsy specimens revealed numerous tumor cells in the dermis and especially in the lumina of lymph and blood vessels. Immunohistochemical studies showed staining with cytokeratin KL1, epithelial membrane antigen, Ca 15-3, and Ca 19-9. Vimentin, S-100 protein, neuron specific enolase, and carcino-embryonic antigen were negative. Treatment with carbon dioxide laser failed. The use of interferon alfa-2a for 9 months stopped progression of the tumor.