Cytodiagnosis of Spindle Cell Squamous Cell Carcinoma presenting as a Metastatic Lesion to Chest Wall: A Case Report

Spindle cell carcinoma is a rare biphasic tumour composed of squamous cell epithelial and spindle cell mesenchymal components. This variant of squamous cell carcinoma masquerades as sarcoma with a high-risk of recurrence and metastasis. Metastatic lesions to the chest wall of squamous cell carcinoma from a distant primary are rare. The most common sites for metastasis from head and neck cancers are usually seen in the lungs, liver, bone, and brain. In this present case, the patient presented with complaints of an ulcerated mass on the left buccal mucosa with limited mouth opening. Despite wide excision of the mass and postoperative radiation, it resulted in distant metastases to the chest wall after a disease-free survival of four months. The metastasis of the chest wall appearing as red, inflamed, small, multiple, subcutaneous nodules is even rarer. The diagnosis of subcutaneous metastatic nodules of squamous cell carcinoma on Fine Needle Aspiration Cytology (FNAC) appearing in the literature is infrequent. The primary in this case was oral squamous cell carcinoma, which in follow-up after wide local excision of the mass with marginal mandibulectomy, presented as multiple inflamed appearing nodules on the chest wall. The primary site of the tumour showing classical squamous cell carcinoma and its metastatic lesion appearing on morphology as the spindle cell variant of squamous cell carcinoma are also infrequently reported in the literature. Herein, one such unusual case of subcutaneous metastasis on the chest wall cytodiagnosed on FNAC is reported.