Vimentin Positive Primary Thyroid Diffuse Large B-Cell Lymphoma: cytological diagnosis of two cases

Primary thyroid lymphomas are rare tumours of thyroid accounting for 5% of all thyroid tumours. Diffuse large B cell lymphoma is one of the most common type of primary thyroid lymphoma. Here we are presenting two rare cases of primary thyroid lymphoma. The first case is of a sixty year old female who presented with a rapidly enlarging thyroid mass, causing compressive symptoms. Radiological investigations revealed deviation and compression of trachea by the mass. Fine needle aspiration was performed, and routine as well as liquid based cytology smears were prepared. Smears revealed features of diffuse large B cell lymphoma of thyroid. Immunocytochemistry was performed that confirmed the diagnosis, and also revealed vimentin positive nature of the neoplasm, that has been shown to confer some degree of resistance to chemotherapy. A tru cut biopsy was performed that reconfirmed the diagnosis, and also helped in determining Ki67 proliferation index of the tumour that determines the aggressive nature of non-Hodgkin’s lymphomas. The second case is of a seventy year old woman who presented with a rapid enlargement of thyroid over a period of three months, leading to difficulty in breathing and dysphagia. Fine needle aspiration was performed that showed features of immunoblastic type of DLBCL. The diagnosis was confirmed by immunocytochemistry, which also showed vimentin positivity. These two cases are important for their rarity, especially being vimentin positive, diagnosed on cytology with the aid of immunocytochemistry. DOI: 10.21276/APALM.1137