A 68-year-old woman with no past history of interest came to the emergency department due to bleeding from a tumour on the left arm. The tumour is large (21x15 cm) and occupies the entire distal half of the arm; it is ulcerated, with necrotic areas, very fragile skin and bleeding. He reports having noticed a small diameter tumour that had been progressively increasing in size over the last 2 years and for which he had never consulted.

In the emergency department, electrocoagulation of the bleeding spot was performed under local anaesthesia and a tissue sample was taken for pathological examination.
She was admitted to hospital and underwent tests. Preoperative tests were performed, as well as diagnostic imaging tests and a tumour extension study. The X-ray of the arm showed a soft tissue mass without bone invasion. The extension study (thoracic-abdomino-pelvic CT scan) showed a pulmonary nodule with well-defined borders and juxtapleural location, located in the upper segment of the left lower lobe, measuring about 6 mm, suggestive of metastasis; it also showed ipsilateral axillary adenopathies.

Biopsy of the tumour reveals an area with massive infiltration of the entire dermis by a fibrohistiocytic proliferation that appears to be low-grade and another necrotic area, suggesting a high-grade proliferation. Malignant fibrohistiocytoma, fibromyxoid sarcoma or myxofibrosarcoma are suggested as differential diagnoses.
Once the studies had been completed, the patient was assessed in a joint clinical session by the Plastic Surgery, Oncology and Thoracic Surgery Departments to decide on the therapeutic approach to be taken. Surgical treatment of the tumour and the application of adjuvant chemotherapy to the pulmonary nodule, which was not considered to require surgical removal, were decided upon.
The intervention consisted of complete resection of the tumour with wide margins and direct closure of the underlying defect. The adjuvant chemotherapy treatment consisted of 6 cycles of Ifosmamide, Mesna, Adriamycin and Dacarbazine.

The anatomopathological study of the excised tumour revealed macroscopically a 21x16x15cm piece, partially lined by skin with important areas of deep ulceration and expansive growth border; on section it presented extensive central areas of necrosis, firm elastic consistency and whitish colouring in the non-necrotic areas and a myxoid appearance in other areas. Microscopic examination revealed an overall nodular pattern, although in many areas it was lost due to the large size of the nodules. Histologically there were highly variable aspects, predominantly areas of sarcomatoid appearance with elongated cells with ovoid nuclei and discreetly acidophilic cytoplasm; in other areas there were variable amounts of mucoid material, areas of myxoid predominance and even clear cartilaginous appearance; the other clearly identified component was epithelial, glanduliform and often cylindromatous. Immunohistochemistry was positive for cytokeratins (AE1-AE3) in epithelial areas and negative in sarcomatoid areas, Vimentin positive in sarcomatous areas and negative in pure epithelial areas, s-100 protein positive in sarcomatoid areas and negative in epithelial areas, EMA positive in epithelial areas, MIB I (proliferation index) very high (50%), Actin and Desmin negative, C-Kit negative. The definitive histological diagnosis was a tumour of epithelial origin with a high degree of malignancy, called malignant chondroid syringoma.

The patient was followed up in the Plastic Surgery outpatient clinic, presenting good scar evolution, with no evidence of recurrence after 2 years. Magnetic resonance imaging (MRI) of the arm showed no evidence of local recurrence. Thoracic-abdominal imaging studies showed a decrease in axillary lymphadenopathy and a pulmonary nodule (4mm). Quarterly check-ups by the Plastic Surgery and Oncology Departments continue to be carried out.

