Anaplastic Large Cell Lymphoma Presenting as a Soft Tissue Mass

Anaplastic large cell lymphoma (ALCL) is a rare tumour, accounting for approximately 3% of adult non-Hodgkin lymphomas.1 Primary systemic ALCL frequently involves both lymph nodes and extranodal sites. A 44-year-old woman presented with a firm, mobile mass in the left iliac fossa region. Ultrasound findings showed a well defined inhomogenous soft tissue mass, measuring 4x4x2.6cm in the deep subcutaneous region. Histopathological examination revealed that the mass was infiltrated by large lymphoid cells with marked nuclear atypia including kidney-shaped nuclei. These neoplastic cells expressed anaplastic lymphoma kinase (ALK) (both nuclear & cytoplasmic staining), CD30 and EMA but not for T-cell (CD45RO and CD3), and B-cell (CD20 & CD79α) markers. Fluorescence in situ hybridization (FISH) analysis showed a t(2;5)(p23;q35) chromosomal translocation. Subsequently the patient developed shortness of the breath and a thoracic computed tomography (CT) scan showed a mass encasing the right upper lobe bronchus. She also had bilateral axillary lymph nodes, measuring 1 cm in diameter (biopsy was not done). The mediastinum and endobronchial region did not show any abnormalities. She received 6 cycles of CHOP chemotherapy and remained disease free 2 years after diagnosis. ALCL, rarely present as a soft tissue tumour and this disease should be included as a differential diagnosis of any soft tissue mass.