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A young man in his early 20s with no prior comorbidities was admitted with complaints of fatigue and generalised weakness for 2 months duration. He also complained of increased frequency of micturition and dragging pain sensation over the abdomen. The patient had lost approximately 15 kg of weight over last 3 months with loss of appetite. He denied history of fever, night sweats, oliguria, dysuria, pedal oedema, frothuria and shortness of breath. On examination, he had pallor, hepatosplenomegaly and bilateral non-tender masses in flank with smooth surface suggestive of renomegaly. There were no peripheral lymphadenopathy, bony tenderness or skin lesions. Laboratory parameters revealed anaemia with haemoglobin of 80 g/L (120–160 g/L), total leucocyte count of 5.5×109/L (4–11×109/L), platelet count of 212×109/L (150–450×109/L), serum creatinine of 70 µmol/L (44–132 µmol/L), serum albumin of 34 g/L (34–54 g/L), lactate dehydrogenase of 355 U/L (normal range 120–220 U/L) and uric acid of 327 µmol/L (89–475 µmol/L). Peripheral blood examination showed neutrophils of 80% with normocytic normochromic anaemia. Unspun urinalysis revealed 1+albumin in dipstick and 2–3 pus cells/high power field with sterile urine culture (significant pyuria). CT of abdomen revealed bilateral symmetrical homogeneous enlarged kidneys measuring 15 cm each without any focal lesion, no dilatation of pelvicalyceal system and decreased contrast perfusion along with retroperitoneal lymphadenopathy and hepatosplenomegaly (figure 1). For evaluation of renomegaly with a possibility of an infiltrative disease, the patient underwent a kidney biopsy. The biopsy revealed sheets of atypical lymphoid cells replacing the entire renal parenchyma with size of around three times that of mature lymphocyte along with coarse chromatin and high nuclear-cytoplasmic ratio. Direct immunofluorescence was negative for immunoglobulins and complements. The patient subsequently underwent a bone marrow biopsy with flow cytometry. It revealed hypercellular marrow with sheets of blasts replacing the granulocytic and erythroid elements (figure 2A,B). On flow cytometry, these blasts were positive for CD19 and CD20 (marker of B lymphocyte), CD5 and CD13 (myeloid lineage marker), CD33 (myeloid marker), CD34 (marker of blast) and myeloperoxidase (MPO myeloid marker) (figure 2C,D); suggestive of Mixed Phenotype Acute Leukaemia (MPAL-mixed myeloid/B cell) with renal infiltration. Remaining work up including echocardiography, funduscopy and cerebrospinal fluid examination for malignant cells were unremarkable. The patient was started on hydration and induction chemotherapy with Modified BFM-95 (Berlin-Frankfurt-Munster) protocol comprising of prednisolone, daunorubicin, vincristine along with intrathecal methotrexate. He did not develop tumour lysis syndrome or renal impairment. Unfortunately, the patient developed a massive middle cerebral artery infarct and expired few weeks after discharge from hospital.
MPAL is a rare clinical entity, accounting for approximately 5% of all acute leukaemias. In 2008, WHO defined MPAL as ‘a single population of blasts that would meet criteria for B-Acute Lymphoblastic Leukaemia or T- Acute Lymphoblastic Leukaemia. It also expresses MPO’ or have ‘unequivocal evidences of monoblastic differentiation’.1 The present case shows a rare occurrence of bilateral nephromegaly secondary to MPAL infiltration at the time of diagnosis. To the best of our knowledge, this is the first adult case reported in literature. The differentials for acquired bilateral nephromegaly in adults include HIV nephropathy, obstructive uropathy, kidney tumours, myelofibrosis with extramedullary hematopoiesis and rarely haematological malignancies like leukaemias/lymphoma infiltration. The most common site of extramedullary involvement in leukaemias are liver, spleen, lymph nodes and skin. Kidneys are a uncommon site for extramedullary dissemination of leukaemias and presentation with bilateral palpable renal masses is very rare. Although leukaemias usually have high total leucocyte counts at presentation, cases of acute leukaemias with nephromegaly and normal counts have been documented.2 The most common imaging finding in renal leukaemic involvement is the presence of focal parenchymal abnormalities with multiple bilateral masses. Other patterns include diffuse bilateral or unilateral involvement and ill-defined parenchymal involvement.3 The prognosis of MPAL is generally poor when compared with de novo AML or ALL.4 This case emphasises the unusual presentation with bilateral nephromegaly and the prompt initiation of four drug induction chemotherapy in the treatment of MPAL.
It is imperative to consider leukaemic infiltration as a cause of bilateral nephromegaly in order to institute timely chemotherapy.
Leukaemic renal infiltration and nephromegaly as a presenting manifestation of acute leukaemia without renal dysfunction or leucocytosis is rare and associated with a poor prognosis.
Massive bilateral renomegaly with maintained renal morphology should be evaluated for storage disorders and blood dyscrasias.
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Contributors AS and APR: manuscript writing; RJ: haematology image acquisition; JS: proof reading and editing.
Funding The authors have not declared a specific grant for this research from any funding agency in the public, commercial or not-for-profit sectors.
Case reports provide a valuable learning resource for the scientific community and can indicate areas of interest for future research. They should not be used in isolation to guide treatment choices or public health policy.
Competing interests None declared.
Provenance and peer review Not commissioned; externally peer reviewed.