A 17-Month-old Boy With Pancytopenia Caused by a Rare Genetic Defect of Vitamin B12 Malabsorption.

Imerslund-Gräsbeck syndrome is an autosomal recessive disorder of vitamin B12 malabsorption presenting with megaloblastic anemia and mild proteinuria in childhood. The disorder is caused by biallelic pathogenic variants in the CUBN or AMN genes, which encode proteins involved in B12 absorption. We present the case of a 17-month-old boy with failure to thrive, pancytopenia, and fevers. His megaloblastic anemia was overlooked leading to unnecessary invasive testing. Findings on bone marrow biopsy prompted investigation for genetic disorders of B12 metabolism. Exome sequencing uncovered 1 known pathogenic variant and 1 novel likely pathogenic variant in CUBN, confirming the diagnosis of Imerslund-Gräsbeck syndrome.

Inflammatory myofibroblastic tumors in children.

BACKGROUND: Inflammatory myofibroblastic tumor (IMFT) is an uncommon neoplasm in children. METHODS: Retrospective review from 1993 to 2014 of patients ≤18years of age with a histopathologic diagnosis of IMFT treated at two tertiary centers. RESULTS: Thirty-two patients were diagnosed with IMFT. Mean (±SD) age was 9.3±5.7years at diagnosis. Tumor location was variable: abdomen/pelvis (28%), head/neck region (22%), intrathoracic (22%), genitourinary (9%), bowel (6%) liver (6%), and musculoskeletal (6%). Median follow-up was 2.6±4.6years, with 3 recurrences and 2 deaths, which occurred only after recurrence. Positive microscopic margin after resection was associated with recurrence, compared to those that had a negative margin (40% vs. 0%, p=0.04). Recurrence was associated with increased mortality (67% vs 0%, p=0.01). Time from first symptoms to resection was shorter in those with recurrence (25.8±22 vs. 179±275days, p=0.01) and in nonsurvivors (44.0±8.0 vs. 194.3±53.4days, p=0.02). Adjuvant chemotherapy, not including steroid monotherapy, either given before or after resection, was administered more often to nonsurvivors (100% vs 4%, p=0.009), and use of corticosteroids was also higher in the nonsurvivors (100% vs. 15%, p=0.04). CONCLUSIONS: IMFT is a rare pediatric neoplasm with variable locations. Complete excision is critical for cure. Proposed guidelines for diagnosis, treatment and surveillance of theses tumors in children are reported.

Differentiating between congenital rhabdomyosarcoma versus fibromatosis of the pediatric tongue.

Congenital rhabdomyosarcoma of the tongue is exceedingly rare. Fibromatosis of the tongue is also rare, and very difficult to distinguish from the spindle cell variant of rhabdomyosarcoma. Both appear histologically as spindle neoplasms replacing normal striated musculature of the tongue. The treatment protocol for the former has been developed by the Intergroup Rhabdomyosarcoma Studies (IRS) I-IV and requires surgery, radiation, and chemotherapy. For fibromatosis, complete surgical excision is usually adequate without additional therapy, although some cases of aggressive fibromatosis also require chemotherapy. With significant differences in appropriate treatment and prognosis, each entity must not be mistaken for the other. We review the differences in radiologic, histologic, and immunohistochemical (IHC) features of both entities.