Tuberculosis and myelofibrosis in children: a report

Tuberculosis and Tumor Lysis Syndrome-Coincidence or Coexistent: A Case Report

Extrapulmonary tuberculosis (TB) involving bone marrow can present with various manifestations, including pancytopenia, maturation arrest, hemophagocytic lymphohistiocytosis (HLH), or infiltration of the bone marrow by caseating or noncaseating granulomas causing reversible or irreversible fibrosis. Tumor lysis syndrome (TLS) is an oncologic emergency resulting from massive tumor cell lysis. Children with TB with bone marrow involvement may also present with laboratory features of TLS resulting from high catabolism and concomitant acute kidney injury (AKI), making the diagnosis difficult at times. We present a case of disseminated TB who presented to emergency with pancytopenia, AKI, and laboratory features of TLS.

Congenital macrothrombocytopenia with focal myelofibrosis due to mutations in human G6b-B is rescued in humanized mice

Unlike primary myelofibrosis (PMF) in adults, myelofibrosis in children is rare. Congenital (inherited) forms of myelofibrosis (cMF) have been described, but the underlying genetic mechanisms remain elusive. Here we describe 4 families with autosomal recessive inherited macrothrombocytopenia with focal myelofibrosis due to germ line loss-of-function mutations in the megakaryocyte-specific immunoreceptor tyrosine-based inhibitory motif (ITIM)-containing receptor G6b-B (G6b, C6orf25, or MPIG6B). Patients presented with a mild-to-moderate bleeding diathesis, macrothrombocytopenia, anemia, leukocytosis and atypical megakaryocytes associated with a distinctive, focal, perimegakaryocytic pattern of bone marrow fibrosis. In addition to identifying the responsible gene, the description of G6b-B as the mutated protein potentially implicates aberrant G6b-B megakaryocytic signaling and activation in the pathogenesis of myelofibrosis. Targeted insertion of human G6b in mice rescued the knockout phenotype and a copy number effect of human G6b-B expression was observed. Homozygous knockin mice expressed 25% of human G6b-B and exhibited a marginal reduction in platelet count and mild alterations in platelet function; these phenotypes were more severe in heterozygous mice that expressed only 12% of human G6b-B. This study establishes G6b-B as a critical regulator of platelet homeostasis in humans and mice. In addition, the humanized G6b mouse will provide an invaluable tool for further investigating the physiological functions of human G6b-B as well as testing the efficacy of drugs targeting this receptor.

Tuberculosis and survival in past populations: A paleo-epidemiological appraisal

Historical assessments of the last two centuries consistently placed tuberculosis as the leading cause of mortality. However, for earlier periods, we can only calculate the frequencies of archaeological bone lesions, which tell us little about the real impact of the disease on mortality. These lesions are usually observed in individuals who have developed immune resistance, which is visible as healed osteo-articular lesions. This study aimed to test the differential impacts of tuberculosis, cribra orbitalia and cribra femoris on adult survival and sex-based survival. We analyzed 28 French adult samples from the Antiquity and the Early Middle Ages. The age-at-death of 1480 individuals was estimated using cementochronology. Survival curves and median age-at-death were calculated to test new hypotheses that challenge the parasitic and deficiency theories of bone stress markers. Comparisons between carriers and non-carriers provided new information concerning the plausible causes of bone stress markers related to infections and TB. The most likely hypothesis is skeletal demineralization and osteoclastic resorption, which are usually observed close to tubercular granuloma or distant from active lesions. The bone marrow niche of Mycobacterium tuberculosis within CD271(+) BM-MSCs stem cells is the proposed explanation for the localized cortical resorption that is observed in bone stress markers.

Paediatric idiopathic myelofibrosis

Pediatric myelofibrosis is a rare disorder. It is usually secondary to other diseases. Rarely, when no underlying cause is found, it is termed idiopathic. We present here, a rare case of idiopathic myelofibrosis in a 10 year old male child. Bone marrow aspirate was dilute. Bone biopsy showed marrow fibrosis, with grade 2-3 reticulin fibres, with no evidence of granuloma, parasite or infilterative disorder. Acid fast bacillus stain was negative. Iliac lymph node biopsy showed reactive sinus histiocytosis with extramedullary hematopoeisis. Thus, diagnosis of pediatric idiopathic primary myelofibrosis was made. Idiopathic pediatric myelofibrosis should be suspected in a child with progressive pallor, hepatosplenomegaly and dry tap on bone marrow aspiration and marrow fibrosis on bone biopsy, after exclusion of secondary causes.

Allogeneic hematopoietic stem cell transplantation for infants with idiopathic myelofibrosis

IMF is a rare disease in children that can present during infancy and has a protracted course. The only known curative approach for this disease in adult patients is allogeneic HSCT. There are very few reports describing the long-term outcome of young children following stem cell transplantation for IMF. We report on eight patients less than two yr of age with IMF that did not resolve with supportive care measures. All patients underwent myeloablative conditioning regimen with busulfan and cyclophosphamide ± ATG followed by HSCT from matched related (n = 6) or unrelated donor (n = 2). All patients achieved neutrophil and platelet engraftment. Four patients had grade II-III acute GVHD, and chronic GVHD developed in five patients (three mild and two severe). At a median follow-up of eight and a half yr (0.7-9), all patients are alive with complete resolution of their hematologic manifestations. At the last follow-up, all patients had normal endocrine function except for one patient who developed hypothyroidism. To date, this is the largest cohort of young children with IMF treated successfully with HSCT, with the longest duration of follow-up. In conclusion, our study showed that HSCT is a curative option for infants with IMF.

Allogeneic cord hematopoietic stem cell transplantation in an infant with primary myelofibrosis

Primary myelofibrosis (PMF) is rare in children. An allogeneic hematopoietic stem cell transplantation (HSCT) is the only known curative therapy for severe cases. Here, we report the case of a female infant with PMF treated with allogeneic HSCT using an unrelated cord blood unit. She had successful reversal of her disease, but experienced complications related to transplant. This is the seventh reported case of HSCT for PMF in children, and the second using umbilical cord blood. We conclude that cord HSCT is a useful curative treatment option in children with PMF, but that efforts must be taken to reduce complications.

Epithelioid hemangioendothelioma presenting with severe myelofibrosis and a high serum hyaluronan level

Epithelioid hemangioendothelioma (EHE) is a rare tumor originating from the vascular endothelium; it has an intermediate malignant potential. EHEs affect all age groups and mostly originate from the soft tissues of the extremities, lungs, and liver. Spinal EHEs, especially those occurring in the bone marrow region, are extremely rare. We report a case of EHE with massive involvement of the liver, vertebrae, and cranial bones that caused severe myelofibrosis (MF) in a 67-yr-old-male patient. Hyaluronan deposits were diffusely observed in the tumor tissue biopsies obtained from both the liver and bone marrow. Furthermore, the serum hyaluronan level increased markedly along with rapid progression of the disease. To the best of our knowledge, this is the first report of MF occurring in an EHE; hyaluronan may have played an important role in the pathogenesis of fibrosis in this case.

Reversible myelofibrosis induced by tuberculosis

Tuberculosis and myelofibrosis are reported in conjunction often enough to raise the possibility that a relationship exists between the 2 entities. However, whether tuberculosis stimulates a secondary fibrotic reaction or develops in patients who have preexisting myeloproliferative disorders is not clear. We describe the case of a 28-year-old man in whom myelofibrosis disappeared completely after administration of antituberculous treatment, which suggests that a causal relationship exists between the 2 disease entities.