(A–C) Marrow films. Marrow has a large population of promyelocytes, which represents the cohort of myeloid cells recovering from agranulocytosis. The alteration may be accompanied by anemia and the marrow may raise concern about promyelocytic leukemia. Over a short period of observation neutrophils begin to enter the blood and marrow granulopoiesis is restored to a normal distribution of precursor cells.
Granuloma. Sarcoidosis. Marrow biopsy. Non-caseating granuloma in marrow. The causes of granulomas in marrow are numerous but fall into five major categories: infection, neoplasm, drug effect, connective tissue diseases, and sarcoidosis. In several studies of this finding the four most common specific causes were tuberculosis, histoplasmosis, sarcoidosis, and lymphoma. Numerous other infectious agents and diseases may result in marrow granulomas. This patient had sarcoidosis.
Granuloma. Tuberculosis. (A) Marrow biopsy. Granuloma in marrow. In several studies of this finding the four most common specific causes were tuberculosis, histoplasmosis, sarcoidosis, and lymphoma. Numerous other infectious agents and diseases may result in marrow granulomas. This patient had tuberculosis. (B) Marrow Biopsy. Ziehl-Neelson Acid-Fast Stain showing Mycobacterium tuberculosis stained red and clustered in macrophages.
Osteopetrosis, a rare bone disease that results from defects in bone resorption as a result of either inability to produce osteoclasts or a functional defect in osteoclasts. The typical finding in blood is a leukoerythroblastic appearance. Blood films. (A) Immature myeloid cell, in this case a myeloblast. (B) Nucleated red cells. Note also teardrop forms. (C) Marrow biopsy section. Markedly thickened bone trabeculae with diminished and fibrotic marrow space (D) Marrow biopsy section. Increased osteoclasts with abnormal or lack of adjacent bone scalloping. (E) Marrow film. Increased osteoclasts confirmed using a tartrate-resistant acid phosphatase (TRAP) cytochemical stain. (F) Characteristic osteoclast. Large cell with multiple discrete nuclei. In this patient, analysis confirmed a mutation in the vacuolar H+-ATPase of the ruffled border, TCIRG1 gene, which can result in osteopetrosis (see review in Bone 42 (2008):19-29).