anemia in the neonatal period is often a complex problem owing to the unique blood picture during this period , the normal variation in hematological parameters , and also because in no other period of life is anemia known to occur due to such varied causes . the common causes of neonatal anemia are rhesus factor ( rh ) and blood group system ( a , b , ab , and o ) incompatibility , hemorrhagic disease of newborn , congenital hemolytic anemia , hemoglobinopathies , and torch ( toxoplasmosis , rubella , cytomegalovirus , herpes virus ) infections . congenital leukemia and osteopetrosis ( op ) are among the very rare causes of neonatal anemia . the neonates with this condition have poor prognosis , with 24 months survival rate of only 23% . the majority of patients ( 80% ) described have acute myeloid leukemia ( aml ) , while 20% have acute lymphoid leukemia ( all ) . the clinical presentations of congenital leukemia include pallor , hepatosplenomegaly , ecchymosis , recurrent infections , and sepsis . although there are reports describing the clinical and hematological profile of congenital leukemia , there are no reports in literature emphasizing the radiological features . op is a rare disorder caused by defective osteoclastic resorption with the infantile ( autosomal recessive ( ar ) ) type having an incidence of 1 in 250,000 births . infantile op presents in neonates with clinical features of marrow failure , anemia , infections , and fractures . we report two cases , one of congenital leukemia and the other of op , both rare diseases . we highlight the radiological and imaging features of congenital leukemia and infantile op and their crucial role in an early diagnosis . a 3-month - old male child presented with history of pallor , abdominal distension , petechial rashes , recurrent respiratory infections , and repeated hospitalization since birth . routine hemogram at our hospital revealed anemia ( hb 6.3 g / dl ) , leukocytosis ( total leukocyte count ( tlc)-83,000 cells / mm ) , and thrombocytopenia ( platelet count-35,000 cells / mm ) . skeletal survey ( x - ray ) requisitioned to rule out congenital infections revealed diffuse osteopenia and prominent calcific zone at metaphyseal ends of the long bones [ figure 1 ] . radiograph of the dorsolumbar spine showed osteopenia with prominent vertebral end plates [ figure 2 ] . the infant showed no facial dysmorphisms suggestive of chromosomal disorder and karyotyping was negative for chromosomal anomalies . the serum biochemical parameters including the liver and renal function tests were within normal limits . the torch serology test for toxoplasmosis , rubella , cytomegalovirus , and herpes virus that includes enzyme - linked immunosorbent assay for detection of immunoglobulin igg antibodies was found to be negative . the radiological and sonographic abnormalities seen in an anemic neonate with negative torch serology , and normal serum biochemical parameters suggested leukemic infiltration . magnetic resonance imaging ( mri ) of the lumbosacral spine and pelvis , revealed abnormal marrow signal intensities in bilateral iliac bones [ figure 4 ] . bone marrow biopsy from the iliac bones revealed marrow infiltration with immature lymphoblasts and diagnosis of acute lymphoblastic leukemia was confirmed [ figure 5 ] . case 1 : 3-month - old male child presenting with symptoms of pallor , abdominal distension , petechial rashes , and recurrent respiratory infections later diagnosed with congenital leukemia . x - ray of both knees and legs , shows diffuse osteopenia with prominent metaphyseal zones ( arrows ) . case 1 : 3-month - old male child presenting with symptoms of pallor , abdominal distension , petechial rashes , and recurrent respiratory infections later diagnosed with congenital leukemia . x - ray of dorsolumbar spine shows osteopenia with prominent vertebral end plates ( arrows ) . case 1 : 3-month - old male child presenting with symptoms of pallor , abdominal distension , petechial rashes , and recurrent respiratory infections later diagnosed with congenital leukemia . ultrasound abdomen shows enlarged liver of 7.52 cm in craniocaudal span with diffuse and homogeneously increased echogenicity ( arrow ) . case 1 : 3-month - old male child presenting with symptoms of pallor , abdominal distension , petechial rashes , and recurrent respiratory infections later diagnosed with congenital leukemia . magnetic resonance imaging ( mri ) of the pelvis in coronal plane using short tau inversion recovery ( stir ) sequence , shows increased marrow signal intensities in both iliac bones ( r  l ) ( arrows ) . case 1 : 3-month - old male child presenting with symptoms of pallor , abdominal distension , petechial rashes , and recurrent respiratory infections later diagnosed with congenital leukemia . bone marrow aspirate from the iliac bone ( leishman stain , 40  ) shows numerous immature lymphoblasts ( black arrows ) . a 3-month - old male infant was also brought with features of pallor , recurrent respiratory infections , and abdominal distension since birth . records of previous hospitalization revealed persistent anemia ( hemoglobin ( hb ) 8.1 g / dl ) and thrombocytopenia ( platelet count-23,000 cells / mm ) . radiographs in this patient revealed diffusely increased bone density with loss of medullary cavity in the long bones [ figures 6 and 7 ] . bone within bone appearance was also noted in the ends of long bones [ figure 6 ] . radiograph of dorsolumbar spine showed increased density of the vertebral body with central linear lucency giving the appearance of radiograph of the skull revealed marked sclerosis of the skull base [ figure 8 ] . computed tomography ( ct ) of the brain done with adequate body lead shielding and using minimal dose , did not reveal any hydrocephalus or cranial nerve compression [ figure 9 ] . bone biopsy revealed disorganized bony trabaculae with obliteration of marrow spaces , which confirmed the diagnosis of op [ figure 10 ] . case 2 : 3-month - old male child presenting with symptoms of pallor , abdominal distension , and recurrent respiratory infections later diagnosed with osteopetrosis . frontal radiograph of right femur shows diffuse increase in bone density with flared metaphysis ( arrow ) . a  bone within a bone  appearance is also observed ( curved arrow ) . case 2 : 3-month - old male child presenting with symptoms of pallor , abdominal distension , and recurrent respiratory infections later diagnosed with osteopetrosis . lateral radiograph of spine reveals sclerosis of vertebral bodies ( curved arrow ) with relative central lucency ( arrows ) ; a characteristic  sandwich vertebra  appearance . case 2 : 3-month - old male child presenting with symptoms of pallor , abdominal distension , and recurrent respiratory infections later diagnosed with osteopetrosis . frontal radiograph of skull shows increased bone density with prominent sclerosis of skull base ( arrows ) . case 2 : 3-month - old male child presenting with symptoms of pallor , abdominal distension , and recurrent respiratory infections later diagnosed with osteopetrosis . noncontrast computed tomography ( ncct ) head shows sclerosis of skull base ( solid arrow ) . case 2 : 3-month - old male child presenting with symptoms of pallor , abdominal distension , and recurrent respiratory infections later diagnosed with osteopetrosis . bone marrow biopsy ( h and e stain , 20 ) shows , disorganized bony trabaculae and obliteration of marrow spaces ( black arrows ) . a 3-month - old male child presented with history of pallor , abdominal distension , petechial rashes , recurrent respiratory infections , and repeated hospitalization since birth . routine hemogram at our hospital revealed anemia ( hb 6.3 g / dl ) , leukocytosis ( total leukocyte count ( tlc)-83,000 cells / mm ) , and thrombocytopenia ( platelet count-35,000 cells / mm ) . skeletal survey ( x - ray ) requisitioned to rule out congenital infections revealed diffuse osteopenia and prominent calcific zone at metaphyseal ends of the long bones [ figure 1 ] . radiograph of the dorsolumbar spine showed osteopenia with prominent vertebral end plates [ figure 2 ] . the infant showed no facial dysmorphisms suggestive of chromosomal disorder and karyotyping was negative for chromosomal anomalies . the serum biochemical parameters including the liver and renal function tests were within normal limits . the torch serology test for toxoplasmosis , rubella , cytomegalovirus , and herpes virus that includes enzyme - linked immunosorbent assay for detection of immunoglobulin igg antibodies was found to be negative . the radiological and sonographic abnormalities seen in an anemic neonate with negative torch serology , and normal serum biochemical parameters suggested leukemic infiltration . magnetic resonance imaging ( mri ) of the lumbosacral spine and pelvis , revealed abnormal marrow signal intensities in bilateral iliac bones [ figure 4 ] . bone marrow biopsy from the iliac bones revealed marrow infiltration with immature lymphoblasts and diagnosis of acute lymphoblastic leukemia was confirmed [ figure 5 ] . case 1 : 3-month - old male child presenting with symptoms of pallor , abdominal distension , petechial rashes , and recurrent respiratory infections later diagnosed with congenital leukemia . x - ray of both knees and legs , shows diffuse osteopenia with prominent metaphyseal zones ( arrows ) . case 1 : 3-month - old male child presenting with symptoms of pallor , abdominal distension , petechial rashes , and recurrent respiratory infections later diagnosed with congenital leukemia . x - ray of dorsolumbar spine shows osteopenia with prominent vertebral end plates ( arrows ) . case 1 : 3-month - old male child presenting with symptoms of pallor , abdominal distension , petechial rashes , and recurrent respiratory infections later diagnosed with congenital leukemia . ultrasound abdomen shows enlarged liver of 7.52 cm in craniocaudal span with diffuse and homogeneously increased echogenicity ( arrow ) . case 1 : 3-month - old male child presenting with symptoms of pallor , abdominal distension , petechial rashes , and recurrent respiratory infections later diagnosed with congenital leukemia . magnetic resonance imaging ( mri ) of the pelvis in coronal plane using short tau inversion recovery ( stir ) sequence , shows increased marrow signal intensities in both iliac bones ( r  l ) ( arrows ) . case 1 : 3-month - old male child presenting with symptoms of pallor , abdominal distension , petechial rashes , and recurrent respiratory infections later diagnosed with congenital leukemia . bone marrow aspirate from the iliac bone ( leishman stain , 40  ) shows numerous immature lymphoblasts ( black arrows ) . a 3-month - old male infant was also brought with features of pallor , recurrent respiratory infections , and abdominal distension since birth . records of previous hospitalization revealed persistent anemia ( hemoglobin ( hb ) 8.1 g / dl ) and thrombocytopenia ( platelet count-23,000 cells / mm ) . radiographs in this patient revealed diffusely increased bone density with loss of medullary cavity in the long bones [ figures 6 and 7 ] . bone within bone appearance was also noted in the ends of long bones [ figure 6 ] . radiograph of dorsolumbar spine showed increased density of the vertebral body with central linear lucency giving the appearance of radiograph of the skull revealed marked sclerosis of the skull base [ figure 8 ] . computed tomography ( ct ) of the brain done with adequate body lead shielding and using minimal dose , did not reveal any hydrocephalus or cranial nerve compression [ figure 9 ] . bone biopsy revealed disorganized bony trabaculae with obliteration of marrow spaces , which confirmed the diagnosis of op [ figure 10 ] . case 2 : 3-month - old male child presenting with symptoms of pallor , abdominal distension , and recurrent respiratory infections later diagnosed with osteopetrosis . frontal radiograph of right femur shows diffuse increase in bone density with flared metaphysis ( arrow ) . a  bone within a bone  appearance is also observed ( curved arrow ) . case 2 : 3-month - old male child presenting with symptoms of pallor , abdominal distension , and recurrent respiratory infections later diagnosed with osteopetrosis . lateral radiograph of spine reveals sclerosis of vertebral bodies ( curved arrow ) with relative central lucency ( arrows ) ; a characteristic  sandwich vertebra  appearance . case 2 : 3-month - old male child presenting with symptoms of pallor , abdominal distension , and recurrent respiratory infections later diagnosed with osteopetrosis . frontal radiograph of skull shows increased bone density with prominent sclerosis of skull base ( arrows ) . case 2 : 3-month - old male child presenting with symptoms of pallor , abdominal distension , and recurrent respiratory infections later diagnosed with osteopetrosis . noncontrast computed tomography ( ncct ) head shows sclerosis of skull base ( solid arrow ) . brain parenchyma and ventricular system are normal . case 2 : 3-month - old male child presenting with symptoms of pallor , abdominal distension , and recurrent respiratory infections later diagnosed with osteopetrosis . 20 ) shows , disorganized bony trabaculae and obliteration of marrow spaces ( black arrows ) . leukemia is a bone marrow infiltrative hematopoietic malignancy causing anemia , thrombocytopenia , hepatosplenomegaly , and occasionally lymphadenopathy . although leukemia is one of the commonest childhood malignancies , neonatal leukemia is rare posing diagnostic challenge to the physician and hematologist with some cases being diagnosed only on post - mortem . in such cases , the radiological features guide the clinician in reaching the final diagnosis . the various radiological findings on conventional imaging include diffuse osteopenia , metaphyseal lucent bands , metaphyseal dense bands , periosteal reaction , and focal lytic lesions . in our first case , the infant had anemia and thrombocytopenia , serum biochemistry was normal and torch serology was negative . however , diffuse osteopenia with prominent calcific metaphyseal zones was documented , which aroused the suspicion of leukemia . mri in this infant showed marrow infiltration in the iliac bones and biopsy from the same site led to the final diagnosis of leukemia . mri of the bone marrow in leukemia has important clinical and prognostic significance and it further helped to clinch the diagnosis in our case . op is a genetically heterogeneous disorder classified as ar and autosomal dominant ( ad ) types . the ar variety , also known as congenital or infantile or malignant op , occurs in infancy and has a rapid downhill course due to severe bone marrow failure . ad variety also known as benign or tarda variety is detected in older children , adolescents , and adults and has a relatively benign course . infantile op manifests in the first few months of life , usually with features of severe bone marrow failure . clinical presentation includes hepatosplenomegaly and failure to thrive , while hematological manifestations are anemia and thrombocytopenia . the increase in bone density due to defective osteoclastic resorption can , however , paradoxically weaken the bone , resulting in a predisposition to fractures . they fracture easily because the bones have disorganized structure and fail to remodel along lines of stress . our second infant presented with features of bone marrow failure such as anemia , thrombocytopenia , and hepatosplenomegaly ( due to extra medullary hematopoiesis ) . correlating the clinical presentation and radiological features of diffusely increased bone density , marked skull base sclerosis , bone within bone appearance in long bones , the radiological diagnosis was infantile op . the radiological appearance in op is characteristic and diagnosis can be made with confidence on the skeletal survey itself . cranial ct and mri are additional investigations to rule out intracranial complications like cranial nerve palsies , ventriculomegaly , atrophy , tonsillar herniation , vertebral artery compression , etc . cranial ct did not reveal hydrocephalus , foraminal compression , or any other abnormalities in our infant . both reported infants had similar clinical presentation of failure to thrive , hepatosplenomegaly , hematological anemia , and thrombocytopenia since birth . in the first infant , the radiological features of osteopenia with prominent metaphyseal bands , increased hepatic echogenicity on sonography , and altered marrow signal of iliac bone on mri , are all explained by leukemic infiltration of bone marrow , liver , and spleen . in the second infant with op , the radiological manifestations of bony sclerosis with bone sclerosis in op , encroaches the medullary cavity , causing marrow failure and pancytopenia , whereas extramedullary hematopoiesis manifests clinically and radiologically as hepatosplenomegaly . however , the hepatic and splenic echogenicity in extramedullary hematopoiesis are normal , in contradiction to the increased echogenicity seen in infiltrative disorders like leukemia . we report two cases where the infants aged 3 months , showed similar clinical and hematological presentations of recurrent infections , anemia , thrombocytopenia , and hepatosplenomegaly since birth . the characteristic radiological and imaging features with appropriate clinical correlation were valuable in arriving at an accurate diagnosis of congenital leukemia and osteopetrosis ( op ) . leukemia and op should be considered in the differential diagnosis of neonatal anemia , in spite of these being rare entities . our report emphasizes the role of radiology in diagnosing two very rare causes of neonatal anemia namely congenital leukemia and op . the importance of skeletal survey and skeletal mri in the workup of such cases is highlighted by our case report .
anemia in neonatal period is rare , with the common causes being rh and abo blood group incompatibility , hemorrhagic disease of newborn , congenital hemolytic anemia , hemoglobinopathies , and torch ( toxoplasmosis , rubella , cytomegalovirus , herpes virus ) infections . 
 congenital leukemia and infantile osteopetrosis ( op ) are among the rare causes of neonatal anemia . 
 a review of the literature shows approximately 200 reported cases of congenital leukemia . 
 articles describing the imaging features of congenital leukemia are still rarer . 
 infantile op , another rare disorder with a reported incidence of 1 in 250,000 has characteristic imaging features , which are diagnostic of the disease . 
 we report a case each , of two rare diseases : congenital leukemia and infantile osteopetrosis . 
 additionally , our report highlights the radiological and imaging features of congenital leukemia and infantile op and their crucial role in arriving at an early diagnosis .