Acute leukemia is the commonest pediatric malignancy with acute lymphoblastic leukemia (ALL) constituting about 75% of all leukemias. ALL commonly presents as fever, bleeding, bone pains, anemia, lymphadenopathy and hepatosplenomegaly. The liver, spleen or lymph nodes are the most common sites of extramedullary involvement in ALL, with renal involvement being relatively uncommon. The usual differential diagnosis of acquired massive bilateral nephromegaly in children includes pyelonephritis, obstructive uropathy, infections such as HIV nephropathy, mucormycosis, glycogen storage diseases, myelofibrosis with extramedullary hematopoiesis, kidney tumors and rarely hematological malignancies like ALL. Here we report a 2 years old child who presented with abdominal distention, low grade fever and constipation. Clinical examination revealed massive bilateral nephromegaly. Preliminary investigations showed severe anemia and slightly elevated WBC counts with presence of reactive changes in lymphocytes along with few atypical cells (9%). Abdominal ultrasonography revealed bilaterally enlarged kidneys which was later confirmed by CT abdomen. He was eventually diagnosed with CALLA positive B cell ALL for which treatment was started in accordance with the International network for cancer treatment and research (INCTR) protocol 02 04. At present, he is on maintenance phase and responding well to the treatment with regression of kidney size to normal on follow up ultrasonogram. Thus, leukemia should be considered in a child presenting with bilateral nephromegaly after exclusion of above mentioned differential diagnosis. Bone marrow aspiration must be done before doing a more invasive investigation like renal biopsy.

Keywords: acute lymphoblastic leukemia, kidney, nephromegaly