Hidradenocarcinomas are rare aggressive skin adnexal tumors of sweat gland origin. It either develops de novo or from preexisting clear-cell hidradenomas. Although hidradenomas presentation is generally benign, they have a high potential for local recurrence, metastasis, and poor outcome 1.
A 65-year-old housewife presented with asymptomatic erythematous plaques with nodular surface on the back of her right ankle of 4-month duration. Physical examination revealed multiple, confluent, erythematous, dome-shaped firm nodules on the medial aspect of her right foot of 1-month duration. Three months later, she developed swelling of the right foot (Fig. 1).
The patient gave a history of screw nail trauma to the sole of the affected foot 1 year ago that was followed by painful edema of the foot that subsided after repeated courses of broad-spectrum antibiotics.
The preliminary differential diagnoses were deep mycoses, eumycetoma, and vascular tumors.
Skin biopsy was taken that showed unremarkable epidermis and a fairly well-circumscribed dermal tumor that was not connected to the epidermis and showed areas of necrosis, mucin deposition, and invasion. The tumor was composed of sheets of biphasic cells, some with eosinophilic cytoplasm and others with clear cytoplasm. The cells were large, atypical, and pleomorphic with hyperchromatic nuclei. There was brisk mitotic activity (Fig. 2). The histopathologic diagnosis was consistent with hidradenocarcinoma.
After this surprising diagnosis that excluded the possibility of deep mycoses and eumycetes, a panel of laboratory and radiologic investigations had been conducted to the patient.
Complete blood count showed anemia (hemoglobin: 9.7 g/dl) with normal leukocytic and platelet counts. Liver and kidney functions were normal. Chest radiography was normal. Pelviabdominal ultrasonography showed fine coarse liver with mildly dilated common bile duct, mild pelvicalyceal splitting due to overdistended urinary bladder and mildly enlarged right inguinal lymph nodes with preserved fatty hilum (14×4 mm). Doppler examination of the right lower limb showed a patent deep venous system but mildly dilated long saphenous vein and superficial varicosities at medial and posterior aspects of the right leg. Doppler examination of the right foot from the palmar surface showed a thick-walled encysted organized collection (4×2 cm) with nonhomogeneous pattern and calcifications (denoting chronicity). Another similar collection at the dorsal surface of the same foot measuring 20×7 mm of the same pattern and likely communicating with deeper collection was seen. Radiography of the right foot showed multiple opacities of the metatarsum with good delineation of the bones, a picture suggestive of osteomyelitis (Fig. 3).
After these investigations, the patient was referred to the Oncology Department. But, the patient was reluctant and went there after 6 months. In the Oncology Department, the patient underwent positron emission tomography scan that showed hepatic and lung metastases. The patient received courses of chemotherapeutics but unfortunately she died.
Hidradenocarcinomas are very uncommon, intradermal malignant tumors of the sweat gland that present as asymptomatic, nondescript cutaneous lesions with reported incidence of around 0.05% in the USA 2. Generally, lesions present initially on the face or on the extremities. However, cases have also been reported on the abdomen, trunk, groin, and even more unusual presentations on the scalp, elbow, and digits. Clinically, the tumor appears as a solitary skin lesion with no characteristic features and may remain dormant or recurs slowly in situ after local excision 3. Metastases have been reported in more than 60% of patients within the first, 2 years, commonly through regional lymph nodes 4. Extensive metastasis through hematogenous routes to the periesophageal, peribronchial, periaortic, and retroperitoneal lymph nodes, bones, vertebrae, ribs, pelvis, lungs, viscera, and the pleura have been reported 1.
Here we reported a case of hidradenocarcinoma with unusual presentation on the right foot that could resemble mycetoma or actinomycetoma, especially after past history of trauma to the same foot.
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1. Gauerke S, Driscoll JJ. Hidradenocarcinomas: a brief review and future directions. Arch Pathol Lab Med 2010; 134:781–785.
2. Cooper P. Carcinoma of sweat glands. Pathol Annu 1987; 22:83–124.
3. Elder D, Elensitas R, Johnson B, Murphy G. Histopathology of the skin, 9th ed. Philadelphia, PA: Lippincott Williams & Wilkins; 2005.
4. Ohta M, Harimoto M, Fuji M, Tojo T. Nodular hidradinocarcinoma on the scalp of a young woman. Dermatol Surg 2004; 30:1265–1268.