A<unk>  (also known as a "malignant mixed tumour" or "MCS" ) is a very uncommon cutaneous (skin) condition characterised by an adnexal eccrine tumour. It is commonly reported to present on the trunk and extremities and behave in an aggressive manner. MCS is a cancerous subtype of its benign counterpart,<unk>  syringoma, and is the least common variation that has an approximated prevalence of less that 0.005%. These tumours mainly arise "from sebaceous glands, sweat glands, and ectopic salivary glands" (Tural, Selçukbiricik, Günver, Karışmaz, and Serdengecti, 2013) and are rarely encountered in radiopathological and clinical practice. The tumours commonly appear with an asymptomatic "slow-growing, painless, solid subcutaneous or intradermal nodules with a normal margin" (Obaidat, Alsaad, and Ghazarian, 2007) and make up for less than one percent of all primary skin tumours. Commonly appearing in the limbs and body, these asymmetrical tumours range from two millimetres to more than three centimetres. MCS is one of the rarest subtypes of tumours and usually requires aggressive surgery to terminate. Despite accounting for only a small number of tumours recorded each year, malignant mixed tumours are easily confused with other skin conditions (such as epidermal cyst, pilar cyst, calcifying epithelioma, or a solitary trichoepithelioma (Tural, Selçukbiricik, Günver, Karışmaz, and Serdengecti, 2013)) and have high potential for recurrence after surgical excision. The aggressiveness of<unk>  varies, as 49% of cases have had local recurrence whereas some demonstrate regional lymph node or osseous metastasis. The rare neoplasms generally do not follow a determinate development path and are often difficult to diagnose. Histologically, these malignant mixed tumours have epithelial and mesenchymal components and are very large, nodular, circumscribed, and nonulcerated. They are morphologically identical to pleomorphic adenoma and have a female predilection. They range from developing deep dermal to subcutaneous nodules and metastasise at a very high rate. Malignant mixed tumours can emerge "de nova or more rarely develop from a cartilaginous syringoma."(IADVL, 2004)
Malignant chondroid syringoma
Neural fibrolipoma
Aggressive angiomyxoma
Malignant acrospiroma
Chondroid syringoma
Peripheral ossifying fibroma
Malignant ectomesenchymoma
Ganglion cyst