A 52-year-old man received HLA-matched sibling allogeneic hematopoietic cell transplantation (alloHCT) for aggressive systemic mastocytosis (ASM) with KITD816V mutation. Diffuse or focal osteosclerosis, common in systemic mastocytosis, was seen in this patient (panels A-B; hematoxylin and eosin [H&E] and mast cell [MC] tryptase immunostain, original magnification ×4). The patient’s bone marrow (BM) aspirates were technically difficult because of osteosclerosis (“dry tap”). Despite no prior documented reports, graft failure was a concern given the osteosclerosis. Neutrophil and platelet engraftment occurred at days 20 and 40 posttransplantation, respectively. The patient achieved a partial reduction in MC burden at 6 months posttransplantation (serum tryptase decreased from 1660 ng/mL to 843 ng/mL), but osteosclerosis persisted. After plateau of the MC burden and serum tryptase levels, cladribine and then midostaurin were used. At 1 year after alloHCT, BM biopsy was technically easier and yielded his first aspirate. MC burden and osteosclerosis (panels C-D; H&E and MC tryptase immunostain, original magnification ×4) were significantly reduced. Serum tryptase was further decreased (400 ng/mL).
In this case, alloHCT and cytoreductive therapy post-alloHCT were not only effective in decreasing MC burden (the maximum immunologic benefit in ASM may be delayed) but also corrected associated bone/BM structural abnormalities.
A 52-year-old man received HLA-matched sibling allogeneic hematopoietic cell transplantation (alloHCT) for aggressive systemic mastocytosis (ASM) with KITD816V mutation. Diffuse or focal osteosclerosis, common in systemic mastocytosis, was seen in this patient (panels A-B; hematoxylin and eosin [H&E] and mast cell [MC] tryptase immunostain, original magnification ×4). The patient’s bone marrow (BM) aspirates were technically difficult because of osteosclerosis (“dry tap”). Despite no prior documented reports, graft failure was a concern given the osteosclerosis. Neutrophil and platelet engraftment occurred at days 20 and 40 posttransplantation, respectively. The patient achieved a partial reduction in MC burden at 6 months posttransplantation (serum tryptase decreased from 1660 ng/mL to 843 ng/mL), but osteosclerosis persisted. After plateau of the MC burden and serum tryptase levels, cladribine and then midostaurin were used. At 1 year after alloHCT, BM biopsy was technically easier and yielded his first aspirate. MC burden and osteosclerosis (panels C-D; H&E and MC tryptase immunostain, original magnification ×4) were significantly reduced. Serum tryptase was further decreased (400 ng/mL).
In this case, alloHCT and cytoreductive therapy post-alloHCT were not only effective in decreasing MC burden (the maximum immunologic benefit in ASM may be delayed) but also corrected associated bone/BM structural abnormalities.
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![A 52-year-old man received HLA-matched sibling allogeneic hematopoietic cell transplantation (alloHCT) for aggressive systemic mastocytosis (ASM) with KITD816V mutation. Diffuse or focal osteosclerosis, common in systemic mastocytosis, was seen in this patient (panels A-B; hematoxylin and eosin [H&E] and mast cell [MC] tryptase immunostain, original magnification ×4). The patient’s bone marrow (BM) aspirates were technically difficult because of osteosclerosis (“dry tap”). Despite no prior documented reports, graft failure was a concern given the osteosclerosis. Neutrophil and platelet engraftment occurred at days 20 and 40 posttransplantation, respectively. The patient achieved a partial reduction in MC burden at 6 months posttransplantation (serum tryptase decreased from 1660 ng/mL to 843 ng/mL), but osteosclerosis persisted. After plateau of the MC burden and serum tryptase levels, cladribine and then midostaurin were used. At 1 year after alloHCT, BM biopsy was technically easier and yielded his first aspirate. MC burden and osteosclerosis (panels C-D; H&E and MC tryptase immunostain, original magnification ×4) were significantly reduced. Serum tryptase was further decreased (400 ng/mL). / In this case, alloHCT and cytoreductive therapy post-alloHCT were not only effective in decreasing MC burden (the maximum immunologic benefit in ASM may be delayed) but also corrected associated bone/BM structural abnormalities.](https://ash.silverchair-cdn.com/ash/content_public/journal/blood/127/14/10.1182_blood-2016-01-690669/4/m_1836f1.jpeg?Expires=1764977780&Signature=Ip9EyLB6I8Ux2iBLhAFHEs1MmY4qG2NGkcjZ9Xa-311rIycruAgdZ60MdHWgtveMLxlDUyzTgWRpBPaQ65BGcOZfvOIYs0gf0yZ7NC9pkBLJpCasyxciTYFc9z9eAl4CSFr5AfJ5wLp0oBer90mu0mxSComRaOvd5GEsNU3MMW7OzCKRlyxoHG7zc1Udm5wiU3VidwUb~cBf5ivsm~x4fylG0~zjx50dr4Wms7Mwbtf5qnETdsadg43kZ3jOHyrO4fb8h-IbojevWYcPHxm3zVbFstopSbrc8LwQoRWNfgbfgYLZVfRIXVBSdlrXyKnci97E21S4K0kdK4Gv6PDSHQ__&Key-Pair-Id=APKAIE5G5CRDK6RD3PGA)
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