To the Editor: Granulocytic sarcoma (GS) (Aka Chloroma / Myeloid sarcoma) is a hematological tumor occurring in extramedullary sites comprising of immature cells of myeloid lineage [1, 2]. It is most commonly associated with acute myeloid leukemia (AML) but also described in other myeloproliferative and myelodysplastic syndromes. The most common sites of involvement are skin, lymph nodes, bone, periosteum, perinueral structures and orbit [3]. Though bilateral orbital proptosis is a common mode of presentation of GS in AML, involvement of the lower urinary tract and especially bladder is extremely rare [3, 4]. An 18-mo-old girl presented with bilateral progressive orbital swelling and intermittent hematuria for 1 mo. Child also had fever and gum swelling for 1 wk. Child was pale and had bilateral periorbital swelling along with hepatosplenomegaly. There was no significant lymphadenopathy or bony tenderness. Blood tests revealed hemoglobin of 5.5 g / dL, total leukocyte count of 6,100/cumm and platelet count of 1.12 lakhs/cumm. Peripheral smear showed moderate hypochromic microcytic erythrocytes with moderate anisopoikilocytosis and predominant lymphocytes. CT abdomen showed polypoid mass lesions in the wall of the bladder measuring 4×2.8 cm (Fig. 1). There was hypotense soft tissue infiltration in maxillary sinuses and floor of orbit on both sides in MRI. Bone marrow aspiration showed 60 % myeloblasts. Biopsy of bladder mass revealed sheets of closely packed small to medium sized, round to oval tumor cells with high N: C ra t io and in te rvening col lagenous s t roma . Immunohistochemistry staining was positive for vimentin, CD34, CD99, CD44, CD117 and MPO in tumor cells and negative for desmin, tDt, CD3, CD4, CD8, CD10 and CD19. Based on morphology and immunohistochemistry, diagnosis of AML with bladder and bilateral retro-orbital GS was confirmed. Child responded well to first cycle of induction chemotherapy but developed severe febrile neutropenia. Child succumbed to uncontrolled sepsis inspite of vigorous antibiotic therapy within 4 wk. GS involving bladder presents with hematuria, dysuria, fatigue, urinary incontinence, urinary retention, suprapubic pain, flank pain and lower abdominal pain [2]. Bone marrow aspiration and biopsy of the mass lesions are mandatory when dealing with doubtful mass lesions in the setting of suspected hematological malignancies. Biopsy with immunohistochemistry is essential for diagnosis as imaging studies are not specific [5]. Positive CD34, CD117, Naphthol-ASDchloracetateesterase (Leder), TdT, myeloperoxidase (MPO) and negative – B-cells (CD20, CD79a), Tcells (CD3,CD45ro), cytokeratin (CK) are the useful markers for clinching the diagnosis [2]. C. G. Delhi Kumar :V. Thilagavathy Department of Pediatric Hemato-Oncology, Institute of Child Heath (ICH), Egmore, Chennai, India