 |
|
Case Reports Indian Pediatrics 2000;37: 790-793 |
|||||||
|
Cranio-Spinal Granulocytic Sarcomas in Childhood Acute Myeloid Leukemia |
|||||||
|
Somashekhar M. Nimbalkar
Granulocytic sarcomas (GS) are extra-medullary tumors of myeloblasts. These tumors constitute a rare, though well-documented, manifestation of acute myeloid leukemia (AML). Their frequency in patients with AML varies from 0.7-5%(1,2). GS may occur in any part of the body, the common sites being the subcutaneous tissue, eye orbits and paranasal sinuses(2). Cranio-spinal involvement is however uncommon. We report here two cases with such involvement.
Case 1: A 17-year-old boy presented in December 1996 with back pain in the mid-thoracic region for one and a half months. He also had tingling sensation in both legs associated with instability of gait, retention of urine and obstipation for 5 days. He denied any history of fever, bleeding, weight loss, anorexia, lymphadenopathy, headache or vomiting. Examination revealed grade 4 power in both lower limbs, and loss of joint position and vibration sensations in both feet. Romberg’s sign was positive. There was no lymph-adenopathy, hepato-splenomegaly or sternal tenderness. Investigations revealed Hb of 15.1 g/dl, total leukocyte count of 19,400/ml with 98% myeloblasts and platelet count of 160,000/ml. Renal and liver function tests were withn normal limits. LDH was increased to 1250 international units (normal: 150-250). T1-weighted, proton density and T2-weighted magnetic resonance (MR) images of the spine showed a mixed-intensity extradural mass lesion at D5-D6 vertebral level (Fig. 1) on the right side with hyperintensity of the spinal cord at D4 to D6 level. Post-contrast study showed enhancement of the mass. It was associated with presence of paravertebral masses. Verte-bral bodies were normal. Fine needle aspiration cytology from the mass showed myeloblasts and promyelocytes. Bone marrow aspiration cofirmed the diagnosis of AML (M2 type) with 50% blasts, which stained with myelo-peroxidase and Sudan black. He was treated with daunorubicin 45 mg/m2 (day 1-3) and cytosine arabinosoide 100 mg/m2 (day 1-7) which resulted in complete remission. Since allogenic bone marrow trans-plant could not be done, he was given consolidation therapy with cytosine arabinoside 100 mg/m2 (day 1-5) and mitoxantrone 10 mg/m2 (day 1-2). Before the second cycle of consolidation, he developed a hematological relapse and declined further treatment. Case 2: A 15-year-old boy presented in March 1999 with bone pains of three-month duration. He also had bleeding and hearing loss in the right ear, and right facial nerve palsy for two months. For the last 15 days, he had noticed multiple swellings over the scalp and jaw. He had received 2 units of blood transfusion for anemia elsewhere. He denied any history of purpura, lymphadenopathy, gum hyperplasia, seizures, headache, vomiting or limb weakness. On examination, he was febrile, pale and had multiple 1 ´ 1 cm size hard swellings over right parietal, left parietal and right mandibular areas. There was evidence of fresh bleeding from the right ear. He also had tenderness over right frontal sinus and sternum. There was no lymphadenopathy or purpura. Liver and spleen were just palpable. Neurological examination revealed infranuclear seventh cranial nerve palsy on the right side. Ocular fundi revealed bilateral retinal bleeds. Investigations showed hemoglobin of 9.2 g/dl, total leukocyte count of 10,600/ml (23% neutrophils, 60% lymphocytes and 17% myelo-blasts) and platelets of 27,000/ml. Activated partial thromboplastin time and prothrombin time were prolonged. Fine needle aspiration cytology from the scalp swellings showed myelomonocytes. Bone marrow aspiration cytology confirmed a diagnosis of acute myelomonocytic leukemia (M4 type); the myeloblasts were positive for myeloperoxidase and butyrate esterase. Cerebrospinal fluid cytology was negative for malignant cells. Computed tomography revealed right side mastoiditis, a middle ear mass and a subdural mass in the right parietal area. MR scan showed evidence of multiple masses, which had mixed intensity on T2-weighted images and were isointense on T1-weighted images (Fig. 2 ). These masses showed enhancement after contrast administration. He was treated with daunorubicin (45 mg/m2/day on days 1-3) and cytosine arabinoside (100 mg/m2/day on days 1-7) which resulted in a complete remission, including resolution of intracranial GS on repeat computed tomogram scan. He also received ‘triple intrathecal therapy’ consisting of cytosine arabinoside, methotrexate and hydrocortisone.
GS are solid tumors of primitive precursors of granulocytic series including myeloblasts, promyelocytes and myelocytes. Since their first description by Dock(3), these tumors have been described in patients with AML, chronic myeloid leukemia and myeloproliferative disorders. GS occur in 0.7% to 5% of patients with AML; this frequency is increasing due to improved survival in AML patients. Most patients are young with 60% being under 20 years of age(3). Both our patients were young. In a recent series(2) of 633 patients with AML, only one case of spinal GS was seen. Our literature search revealed only 38 cases of cranio-spinal GS (17 cranial, 21 spinal). Spinal involvement is usually in the form of extradural mass; intramedullary masses are extremely rare(4). Middle ear involvement, as seen in our case 2, has previously been reported earlier in only two patients; both these patients also had facial nerve palsy(5). MR imaging may allow distinction of GS from abscesses and hematomas; they are isointense relative to the white matter of the brain and bone marrow on T2-weighted images, and isointense to the cerebral gray matter on T1-weighted images. However, GS with mixed intensity, as observed in both our cases are difficult to differentiate from abscesses. Bone involvement is typically subperio-steal. It has been postulated that leukemic cells migrate to the periosteum from the bone marrow through haversian canals. The cells may then invade the duramater. The brain is infiltrated by direct spread from arachnoid mater. Meningeal involvement is being increasingly recognized due to improved survival and thus in pediatric cases central nervous system prophylaxis is recommended. GS may present prior to(6) or concurrently with other manifestations of AML, as was seen in both our cases. It may also occur when the patient is in hematological remission, signifying a disease-relapse. Presence of GS should lead to a search for leukemia. GS resolve promptly after treatment with chemotherapy, radiation or both(7). Both our patients also had rapid resolution of their neurological deficit. Surgery is, therefore, indicated only if there is rapid progression of neurological deficit or when diagnosis is in doubt.
|
