The tumour is described as invasive and is clinically characterised by faster growth than the benign chondroid syringoma. They can generally be diagnosed when presenting "an epithelial component, eccrine or apocrine differentiation and myoepithelial component of fluctuating prominence" (IADVL, 2004). Diagnosis is recommended to follow microscopic analysis to ensure correct examination. Treatment
There currently is no established guideline for the standardised treatment of malignant chondroid syringomas, due to their rarity. However, the efficacy of treatment for malignant mixed tumours depends on the time of diagnosis. An immediate and broad surgical excision "with clear margins" (Tural, Selçukbiricik, Günver, Karışmaz, and Serdengecti, 2013) is considered curative and to be the most successful treatment. This treatment aims for the most efficacious disease control. It is largely agreed that chemotherapy and radiotherapy are ineffective yet are sometimes still recommended, yet radiotherapy reacts positively to skeletal metastasis. Combination chemotherapy for MCS is reported as unbeneficial. MCS is reported to have a high and continual risk of recurrence of metastasis, some patients experiencing metastasis nearly twenty years after the primary examination. Thus this necessitates consistent clinical follow-up in order to maintain a benign state of the tumour and achieve disease control. Prognosis
Malignant mixed tumours have a poor prognosis that is deemed unpredictable due to its spread being lymphatic or blood-borne. As there have only been a limited number of cases that have been reported, prognostic points are challenging to confirm, however mainly "include size, histological type, lymph node involvement, and distant metastasis" (Garcia, Atun, and Fernando, 2016).
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)

Causes
Currently malignant mixed tumours do not have a definitive predisposing factor; however, prior physical injury has been proposed as a potential risk for the emergence of these tumours. Chondroid syringoma less than three centimetres are shown to have a heightened risk of malignancy. Other critical indicators include excessive mucoid matrix, – a connective tissue tumour with a myxoid background that is composed of "clear, mucoid substance – numerous mitoses, and poorly differentiated chondroid components." (Metzler, Schaumburg-Lever, Hornstein, and Rassner, 1996)

Diagnosis
Diagnosing malignant mixed tumours is difficult as there many types of tumours and their variants. Malignant chondroid syringoma is particularly challenging to distinguish from other skin tumours as it is prone to the absence of definitive symptoms and an ambiguous clinical presentation. Some signs that help determine diagnosis of malignancy include: "mitosis, nuclear atypia, pleomorphism, lymphatic invasion, and local recurrence" (IADVL, 2004). Though it is usually found within women in the forties, the youngest-recorded case was fourteen years old and the oldest was eighty-six.