Sarcoidosis may affect the bone marrow, causing refractory cytopenias.
Presentations may include:
(1) fever of unknown origin (FUO)
(2) any combination of anemia, leucopenia and thrombocytopenia
(3) diffuse bone marrow uptake on PET scan
(4) incidental finding on a bone marrow examination
(5) workup for metastatic carcinoma or myelodysplasia in an older adult
The diagnosis is considered by the presence of noncaseating granulomas on a bone marrow core biopsy with negative stains for fungi and mycobacteria.
The major problem in diagnosis is exclusion of other causes (infection, drugs, etc). Sarcoid-like reactions may be associated with a variety of neoplasms.
The presence of sarcoid-like findings in other organs (lungs, lymph nodes, etc) can be helpful in establishing the diagnosis.
The diagnosis may be supported by an elevated serum angiotensin-1 converting enzyme (ACE) activity.
One clue to the diagnosis may be an improvement in anemia after starting corticosteroid or immunosuppressive (methrotrexate, mycophenolate mofetil, etc). therapy.
