Poroid hidradenocarcinoma and atypical hidradenoma papilliferum of the vulva – Two cases

Abstract

Benign and malignant tumours may arise from eccrine and apocrine sweat glands. Hidradenocarcinoma is a rare malignant eccrine sweat gland tumour representing <0.01% of all skin cancers. There are 6 case reports in the literature of hidradenocarcinoma arising on the vulva, none of which are classified as poroid hidradenocarcinoma. Hidradenocarcinoma is thought to be an aggressive tumour with poor prognosis and high levels of local recurrence and systemic metastases. Conversely, hidradenoma papilliferum is a common benign apocrine sweat gland tumour found on the vulva. The prevalence and significance of atypical changes, however, is unknown. Distinguishing between these tumour types can be difficult. The authors present two cases, a poroid hidradenocarcinoma and an atypical hidradenoma papilliferum with necrosis and increased mitotic activity, to illustrate the diagnostic challenges associated with rare tumours of the vulva in the absence of an established histopathological classification system.

Hidradenocarcinoma of the Left Knee in a 55-Year-Old Woman: A Case Report

“…Hidradenocarcinoma is the malignant counterpart of hidradenoma, an eccrine sweat gland tumor. This uncommon phenomenon is referred to by a variety of medical terms, including clear cell hidradenocarcinoma, malignant clear cell myoepithelioma, clear cell eccrine carcinoma, primary mucoepidermoid cutaneous carcinoma, and malignant acrospiroma [ 3 , 4 ]. It has been estimated that 6-7% of benign neoplasms will mysteriously convert into malignant tumors [ 9 ].…”

“…It usually presents as a slow-growing, nodular, solid, and cystic cutaneous mass associated with serous discharge or ulceration [ 4 ]. The benign histopathological variants are clear cell, solid cystic, mucinous, poroid, and pigmented nodular hidradenoma [ 4 , 5 ]. The benign lesions can undergo malignant transformation, though very rarely [ 6 ].…”