Bone marrow nonneoplastic
Alterations in cellularity
Amegakaryocytosis
Author: Dragos C. Luca, M.D.
Last author update: 1 March 2013
Last staff update: 2 October 2023
Copyright: 2002-2024, PathologyOutlines.com, Inc.
PubMed Search: Bone marrow amegakaryocytic thrombocytopenia
Cite this page: Luca DC. Amegakaryocytosis. PathologyOutlines.com website. https://www.pathologyoutlines.com/topic/bonemarrowamegakaryocyticthrombocytopenia.html. Accessed December 23rd, 2024.
Amegakaryocytic thrombocytopenia
Definition / general
Etiology
Clinical features and diagnosis
Case reports
Treatment and prognosis
Microscopic (histologic) images
Images hosted on other servers:
- Also called CAMT (congenital amegakaryocytic thrombocytopenia)
- Extremely rare, usually diagnosed in early childhood (Pediatr Blood Cancer 2011;57:199, Hematol Oncol Clin North Am 2009;23:321)
- Initially thought to have variable inheritance (autosomal recessive or X linked) but X linked forms now reinterpreted as mild or attenuated forms of Wiskott-Aldrich syndrome
Etiology
- Most cases caused by homozygous (biallelic) or compound heterozygous mutations in thrombopoietin (TPO) receptor gene c-mpl at 1p34 (Blood 2001;97:139), causing impaired expression of c-mpl gene, causing defective response to TPO (OMIM: Amegakaryocytic Thrombocytopenia, Congenital; CAMT)
- Missense mutations associated with milder or delayed course vs. loss of function mutations (Hum Mutat 2006;27:296)
Clinical features and diagnosis
- Isolated nonimmune thrombocytopenia with decreased marrow megakaryocytes and high serum TPO levels
- Red cell macrocytosis with normal hemoglobin level
- Bone marrow initially normocellular
- Mucocutaneous or GI bleeding, variable physical abnormalities (Br J Haematol 2005;131:636)
Case reports
- Girl with developmental delay, facial malformations and CNS anomalies (Pediatr Blood Cancer 2011;56:452)
- 61 year old woman with systemic sclerosis and anti-c-mpl antibody (Arthritis Rheum 2003;48:1647)
Treatment and prognosis
- Stem cell transplantation
- 50% evolve to aplastic anemia (at mean age 3.5 years); may evolve to myelodysplastic syndrome or leukemia
Microscopic (histologic) images
Images hosted on other servers:
Bone marrow aspiration and trephine biopsy
Bone marrow failure in child
Congenital
[Pending]
Secondary
[Pending]
