A malignant chondroid syringoma (also known as a "malignant mixed tumour" or "MCS" ) is a very uncommon cutaneous (skin) condition characterised by an adnexal eccrine tumour. : 667 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, chondroid 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 malignant chondroid syringoma varies, as 49% of cases have had local recurrence whereas some demonstrate regional lymph node or osseous metastasis.
The findings were as follows.“The surgical specimen showed a lobular proliferation of tumour cells with glandular differentiation associated with a few mitotic cells, embedded in a mucinous stroma. Immunohistochemistry showed that the majority of tumour cells were positive for PAS diastase, toluidine blue, cytokeratins (CAM5.2, CK7), S-100 protein and GCDFP-15.”Although some abnormal tumours cells were present, the recorded findings the man was diagnosed with chondroid syringoma. An ultrasound and radiography were performed and revealed no indication of metastasis. However, in 2008, the man observed inflammation in his right groin area. Another ultrasound revealed a new mass also measuring 30 mm x 30mm, which was then excised. Examination of this new tumour revealed more abnormal tumour cells compared to the first nodule of the sole of the foot. The original diagnosis was thus re-examined to be consisting of malignant chondroid syringoma cells. The patient was then treated with radiation. After eighteen months he presented no evidence of recurrence or further distant metastasis. History
Hirsch and Helwig gave malignant chondroid syringoma its name in 1961 in ‘Chondroid Syringoma: Mixed Tumour of Skin, Salivary Gland Type.’ "Atypical mixed tumours of the skin,"(Hirsch and Helwig, 1961) their term for tumours characterised by "histological stigma of malignancy, local invasion, and satellite tumour nodules without proven metastases" is employed even now. As of 2011, only 43 cases have been reported. Terminology
Malignant mixed tumours also go by other names including: "malignant mixed tumour of skin, cutaneous malignant mixed tumour, metastasising chondroid syringoma, and aggressive chondroid syringoma."