Malignant eccrine spiradenoma: An unusual presentation

Introduction

Eccrine spiradenoma is a well recognized benign sweat gland tumour arising from the intradermal straight part of the duct of eccrine sweat glands. Although benign forms are not uncommon, malignant transformation of this tumour is rare. We present a patient with spiradenoma in the lower limb with malignant transformation and multiple satellite nodules associated with lymphedema of the involved limb.

Case Report

A 60-year-old woman presented with a 6 month history of a progressively increasing painles nodule in her right groin which had assumed the form of a large plaque-like lesion with an ulcerated surface discharging serous fluid. The primary lesion was associated with the appearance of a crop of multiple nodules involving the thigh and a progressive swelling of her entire right lower limb. Physical examination revealed a massive pitting lymphedema of the right lower limb. In the inguinal region there was a large (10 x 5 cm) indurated plaque like lesion with irregular raised margins and ulcerated surface [Figure - 1].

Necrotic slough was present on the surface of lesion with a persistent serous discharge. Another similar but smaller lesion was present on the medial aspect of upper one third of thigh. Multiple satellite nodules, majority of which were ulcerated, were scattered all over. There were no palpable inguinal lymph nodes. Histological examination of punch biopsy specimens from the main lesion and one of the nodules established the diagnosis of benign eccrine spiradenoma [Figure - 2] However histology from another excised nodule revealed low grade spiradenocarcinoma with areas of transition [Figure - 3]. Chest radiographs and abdominal ultrasound failed to reveal any evidence of metastatic lesion. Since the local extent of the tumour ruled out any attempt at curative resection the patient was treated with palliative radiotherapy of the local site with the hope of achieving some degree of local control of disease.

Discussion

Eccrine spiradenoma is a benign tumour of sweat gland origin which was first described by Kersting and Helwing in 1956. It is a relatively uncommon tumour appearing mainly in young adults without any sex prediliction. The tumour usually presents as a solitary firm round dermal nodule on any part of the body but most frequently on the face, scalp, trunk and proximal parts of limbs. Infrequently multiple lesions are present which may become confluent or remain discrete. The overlying epidermis may show no change in colour or may be pinkish and rarely ulcerated.

Malignant transformation of an eccrine spidenoma is a rare phenomenon with less than a score of cases having been previously reported.[2],[4] Malignant change occurs either within a preexisting spiradenoma or may appear as a satellite nodule, as in this case.

The appropriate therapy of malignant eccrine spiradenoma consists of a wide local excision with resection of clinically suspicious lymph nodes. Irradiation of the resection site can be useful in preventing local recurrence. The role of chemotherapy is not yet clearly defined.

The motive behind presenting this case was to highlight some of its very singular features malignant transformation in satellite nodule and association with a massive lymphedema of the involved limb make this case unique. Besides this, an older age of presentation, multiplicity and ulceration of lesions are other rare features.