Marrow hypoplasia: a rare complication of untreated Grave's disease.

Atypical presentation forms of hyperthyroidism are always a challenge to the clinician. We present a female patient with the typical symptoms of thyrotoxicosis, without any thionamides treatment before, associated with pancytopenia, which recovered after euthyroidism state was achieved. Although the major cases of pancytopenia in Grave's disease are seen as a complication of antithyroid drugs (thioamides), in this case report the alteration in blood tests was associated with untreated hyperthyroidism. In the literature review, we found 19 case reports between 1981 to 2012, but it has been related to a hypercellular bone marrow with periferic destruction. Our case, however, is about a hypocellular bone marrow without fibrosis or fat tissue replacement, which proceeded with a periferic improvement following thyroid treatment. Although rare, pancytopenia, when present, may develop as an unusual and severe manifestation in untreated subjects.