Malignant Eccrine Spiradenoma (Spiradenocarcinoma)

Abstract

Malignant eccrine spiradenoma is a very rare tumor. The clinicopathologic features of 12 cases are reported herein. Six patients were men, six were women, and the average patient age was 62 years. Seven tumors were located on the trunk, three on the extremities, and two in the head and neck region. All tumors were large (average size-7.5 cm). Lesions had been present from 7 months to 30 years before surgical removal. In all cases, continuity between benign eccrine spiradenoma and areas with malignant change was observed. Malignancy was evidenced by increased mitotic rate, necrosis, nuclear atypia, pleomorphism, and hyperchromasia, loss of nested and trabecular growth patterns, and absence of a dual cell population. In most cases (8 of 12), the malignant component comprised the bulk of the lesion. Two distinctive histologic patterns were observed. Five of 12 tumors exhibited abrupt transition between a benign eccrine spiradenoma and a high-grade carcinoma component. The others lacked a clear-cut transition between benign and malignant components and were diagnostically challenging. Diagnosis in such cases was established based on the loss of two cell populations, increased nuclear to cytoplasmic ratio, hyperchromasia, and marked mitotic activity. Two tumors showed focal squamous differentiation. Five of seven patients on whom there was follow-up information were free of disease (average duration of follow-up = 3.4 years). One patient developed metastases to local lymph nodes 5 years after the primary tumor was resected. This patient had no evidence of disease 16 months after resection of her lymph node metastases.

Morphologically low-grade spiradenocarcinoma: a clinicopathologic study of 19 cases with emphasis on outcome and MYB expression

“…1,2,14 Histologically, the disease spectrum is separated into tumors with morphologically low-and high-grade features. 14 Kazakov et al 2 have further subdivided the histological patterns according to their similarities to tumors of the salivary glands into basal cell adenocarcinoma, low-grade; basal cell adenocarcinoma, high-grade; invasive adenocarcinoma, not otherwise specified; and sarcomatoid/metaplastic carcinoma. Spiradenocarcinoma showing low-grade morphology as the sole malignant component and the rare metaplastic carcinomas are currently thought to pursue a more indolent disease course.…”

“…5,[11][12][13] Malignant transformation in eccrine spiradenoma, dermal cylindroma, and cylindroma-spiradenoma hybrid tumors is a rare event with only~150 cases documented in the literature. 1,2,14 The malignant component shows a wide morphological spectrum, ranging from outright invasive adenocarcinoma to more innocuous appearances, reminiscent of basal cell adenocarcinoma of the salivary gland. 2 The tumors have therefore been separated histologically into morphologically low-and high-grade.…”

“…2 The tumors have therefore been separated histologically into morphologically low-and high-grade. 2,14 Their diagnosis depends entirely on adequate sampling and recognition of a pre-existing benign component, most commonly a benign spiradenoma. The morphologically low-grade malignant tumors pose a particular diagnostic challenge owing to their subtle histological changes, characterized by loss of a dual cell population, monotonous cellular growth, increased mitotic activity but only limited cytological atypia.…”

“…The morphologically low-grade malignant tumors pose a particular diagnostic challenge owing to their subtle histological changes, characterized by loss of a dual cell population, monotonous cellular growth, increased mitotic activity but only limited cytological atypia. 2,14 Although traditionally thought of as highgrade skin adnexal carcinomas with aggressive behavior and potential for metastatic spread and associated mortality, more recent studies have suggested a more indolent disease course with favorable outcome, at least for the morphologically low-grade tumors. 1,2,14,15 However, only 18 such cases have been reported with limited available follow-up.…”

“…2,14 Although traditionally thought of as highgrade skin adnexal carcinomas with aggressive behavior and potential for metastatic spread and associated mortality, more recent studies have suggested a more indolent disease course with favorable outcome, at least for the morphologically low-grade tumors. 1,2,14,15 However, only 18 such cases have been reported with limited available follow-up. The aim of the present study was to study the outcome of morphologically low-grade malignant spiradenocarcinomas more comprehensively on a larger cohort with long-term follow-up.…”