CYTO HISTOLOGIC CORRELATION OF A LOW GRADE FIBROMYXOID SARCOMAAT AN UNUSUAL LOCATION – A CASE REPORT

Abstract

BACKGROUND Low grade fibromyxoid sarcoma (LGFMS) is a rare tumour of the deep soft tissues seen in young adults. The histologic features of LGFMS are well established, however the cytologic findings are scantily defined and the distinction from other benign and malignant myxoid soft tissue tumours is difficult. CASE DETAILS A 29 year old male presented with a superficial swelling in the left areolar region for two months. USG revealed a well-defined 2 by 2 cm hyperechoic lesion extending upto the subcutaneous fat. FNA yielded mucoid material and smears showed spindle cells having round to elongated nuclei with mild anisokaryosis, bland chromatin and wispy cytoplasm in a myxoid background. No significant nuclear pleomorphism or mitoses were noted. A diagnosis of myxoid mesenchymal lesion was made. The excised tumour was well circumscribed with grey white cut surface showing myxoid areas. Microscopically, the tumour displayed moderate cellularity with storiform, intersecting and parallel bundles of spindle cells showing mild nuclear pleomorphism. The myxoid areas showed cells in a haphazard fashion floating in abundant mucoid matrix associated with a capillary network. The mitotic index was low. IHC showed tumor cells positive for vimentin and negative for S-100 & SMA. CONCLUSION LGFMS is a rare low-grade malignancy with a high local recurrence rate and late metastasis. The diagnosis of LGFMS can be difficult to render from fine needle aspiration cytology (FNAC) alone because of morphological overlap with other spindle cell and myxoid lesions. Cytohistological correlation and IHC is helpful in arriving at a correct diagnosis.