https://orcid.org/0000-0003-0077-640X
![A 59-year-old woman with a known history of JAK-2+ (V617F) polycythemia vera (PV) previously managed with venesections was referred for possible progression to post-PV myelofibrosis on the basis of a leucoerythroblastic blood film, raised lactate dehydrogenase (LDH), and newly palpable splenomegaly (palpable at 1 cm below the rib cage). The patient had a significant history of metochondromatosis (a rare autosomal disorder resulting in enchondromas and osteochondroma-like lesions). Bone marrow trephine demonstrated infiltration, with numerous chondromas (panel A; hematoxylin and eosin [H&E] stain; original magnification of bone marrow trephine ×20; black arrow indicates chondromas). Only small areas of hematopoiesis remained and had preserved trilineage hematopoiesis (panel B; H&E stain; original magnification ×40), and reticulin stain demonstrated no increased reticulin deposition or fibrosis (panel C; reticulin stain; magnification ×40). She therefore did not meet the diagnostic criteria for post-PV myelofibrosis, with splenomegaly likely a result of extramedullary hematopoiesis.](https://ash.silverchair-cdn.com/ash/content_public/journal/blood/138/22/10.1182_blood.2021013420/5/m_bloodbld2021013420f1.png?Expires=1765981845&Signature=KBa~8WXIZfn4vZeODB840sNPWpH7zh1pDg~5bNEYLQgoxb4FGFmWAzqhmQeVaZu-V6j-1sTbigsG3isa3XsmhZ8aNvWg1XCZm0HW6OCuw17JiV4LewQGzuvV-PL-bZPllQjPRIX7hpuPfIuUE7sNXY27w-TL3WsDV~ZkBb~Eg8H3z29F3HAaA-eWv21GmxREBHUZLOUN0j2GXot9CyHr2WkA4N~7RTRzW7UKf45YFUMrxLrSdI0ldPZkpygN0Ohy~6iKsIeb1~c6cX~KbwBbjX~UfFbCLEzOAQBkzYefNQAYW9gCgyJsHUOEz~Mq5gLTiNzdJNuR42c7ORUr0BWgJw__&Key-Pair-Id=APKAIE5G5CRDK6RD3PGA)
A 59-year-old woman with a known history of JAK-2+ (V617F) polycythemia vera (PV) previously managed with venesections was referred for possible progression to post-PV myelofibrosis on the basis of a leucoerythroblastic blood film, raised lactate dehydrogenase (LDH), and newly palpable splenomegaly (palpable at 1 cm below the rib cage). The patient had a significant history of metochondromatosis (a rare autosomal disorder resulting in enchondromas and osteochondroma-like lesions). Bone marrow trephine demonstrated infiltration, with numerous chondromas (panel A; hematoxylin and eosin [H&E] stain; original magnification of bone marrow trephine ×20; black arrow indicates chondromas). Only small areas of hematopoiesis remained and had preserved trilineage hematopoiesis (panel B; H&E stain; original magnification ×40), and reticulin stain demonstrated no increased reticulin deposition or fibrosis (panel C; reticulin stain; magnification ×40). She therefore did not meet the diagnostic criteria for post-PV myelofibrosis, with splenomegaly likely a result of extramedullary hematopoiesis.
Post-PV myelofibrosis is diagnosed on the basis of both clinical features (eg, anemia or loss of requirement for venesection, splenomegaly, or constitutional symptoms) and pathological/histological findings (eg, grade 2-3 marrow fibrosis or raised LDH). Clinicians should be aware that other conditions can cause a similar picture, including marrow infiltration with both benign (as in our case) and malignant tumors.
A 59-year-old woman with a known history of JAK-2+ (V617F) polycythemia vera (PV) previously managed with venesections was referred for possible progression to post-PV myelofibrosis on the basis of a leucoerythroblastic blood film, raised lactate dehydrogenase (LDH), and newly palpable splenomegaly (palpable at 1 cm below the rib cage). The patient had a significant history of metochondromatosis (a rare autosomal disorder resulting in enchondromas and osteochondroma-like lesions). Bone marrow trephine demonstrated infiltration, with numerous chondromas (panel A; hematoxylin and eosin [H&E] stain; original magnification of bone marrow trephine ×20; black arrow indicates chondromas). Only small areas of hematopoiesis remained and had preserved trilineage hematopoiesis (panel B; H&E stain; original magnification ×40), and reticulin stain demonstrated no increased reticulin deposition or fibrosis (panel C; reticulin stain; magnification ×40). She therefore did not meet the diagnostic criteria for post-PV myelofibrosis, with splenomegaly likely a result of extramedullary hematopoiesis.
Post-PV myelofibrosis is diagnosed on the basis of both clinical features (eg, anemia or loss of requirement for venesection, splenomegaly, or constitutional symptoms) and pathological/histological findings (eg, grade 2-3 marrow fibrosis or raised LDH). Clinicians should be aware that other conditions can cause a similar picture, including marrow infiltration with both benign (as in our case) and malignant tumors.
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