Primary cutaneous leiomyosarcoma: A rare malignant neoplasm
A 70-year-old male patient presented with a painful nodule in the right leg, which had been progressively increasing in size for 4 months. On palpation, an irregular, firm, tender exophytic swelling, measuring 5 cm × 5 cm, with overlying skin showing ulceration was noted on the lateral aspect of the lower one third of the right leg []. Inguinal lymph nodes were not palpable. His past history was significant of a trauma and subsequent non-healing ulcer formation at the same site in the right leg.\nSystemic examination and investigations, including complete blood count, fasting blood sugar level, liver function test and renal function test, were within normal limits. Hepatitis B virus surface antigen and human immunodeficiency virus enzyme-linked immunosorbent assay were non-reactive.\nA clinical diagnosis of squamous cell carcinoma was considered and fine needle aspiration cytology of the swelling was requested.\nFine needle aspiration cytology of the same was reported as a spindle cell neoplasm with suspicion of malignancy. The swelling was excised with a 5 cm resection margin and submitted for histopathological examination [].\nGross inspection revealed a grey brown, irregular, nodular soft tissue mass, measuring 5 cm × 5 cm × 2.5 cm and partly covered with skin. The cut surface of the mass was greyish white, solid, homogenous and fleshy [].\nLight microscopy revealed a poorly delineated dermal neoplasm extending into the underlying subcutis. The neoplasm was composed of bundles of elongated spindle cells arranged in interlacing fascicles, with intensely pink, fibrillary cytoplasm and pleomorphic nuclei with coarse irregularly dispersed chromatin. Mitosis, including atypical, amounting to 22 mitotic figures per 10 high power fields and multinucleate tumor giant cells, was evident. Focal necrosis was noted at the edges. The overlying epidermis was thinned out with areas of ulceration [].\nA provisional diagnosis of spindle cell malignant neoplasm of the skin, which typically includes a host of diagnostic possibility, namely fibrosarcoma, leiomyosarcoma, malignant peripheral nerve sheath tumor, monophasic synovial sarcoma, malignant fibrous histiocytoma and spindle cell variant of squamous cell carcinoma, was considered and immunohistochemistry was advised for confirmation.\nOn immunohistochemistry, tumor cells showed strong immunopositivity for vimentin, muscle-specific actin (MSA), smooth muscle actin (SMA), caldesmon and desmin and negative for pancytokeratin, Epithelial Membrane Antigen (EMA), myogenin, CD34 and S-100 protein [].\nBased on the immunophenotypic features, a final diagnosis of PCL was rendered. The patient is currently on periodic follow-up since 1 year and no recurrence or metastasis has been identified so far.