Beyond the Marrow: Unveiling Uncommon Sites of ALL Relapse with 18 F-FDG PET/CT.

Extramedullary infiltration of acute lymphoblastic leukemia/lymphoma (ALL) to genital organs is extremely rare. Here, we present a case report of an asymptomatic 49-year-old female, known case of precursor B-cell ALL, who was incidentally detected with thickened and heterogeneously hyperechoic endometrium on sonography. Contrast magnetic resonance imaging detected large polypoidal enhancing lesions showing intense diffusion restriction occupying the endometrial cavity and similar lesions in the left adnexa, left ovary, and fallopian tube which were suspicious for leukemic infiltration because of the clinical history and atypical appearance of the lesions. ¹⁸ F-fluorodeoxyglucose positron emission tomography/computed tomography ( ¹⁸ F-FDG PET/CT) was done which revealed intensely metabolically active lesion in the endometrial cavity, left adnexa, omental nodules, retroperitoneal lymph node, pancreatic lesion, and few irregular nodules in the right lower lobe. Biopsy findings confirmed extramedullary relapse of ALL. Hence, ¹⁸ F-FDG PET/CT can act as a good whole body survey to look for extramedullary sites of relapse.