An isolated inflammatory myofibroblastic tumor of adrenal gland.

Inflammatory myofibroblastic tumor (IMT) is an uncommon lesion that shows a wide range of anatomic distribution. The adrenal gland, however, is a distinctly rare site of occurrence. To date, only a few cases of IMT arising in the adrenal gland have been reported in the English literature. Here, we report another case of isolated adrenal IMT. A 34-year-old man presented to the emergency department with a complaint of a sudden severe right-sided back pain. Subsequent computed tomographic scan imaging studies demonstrated a large right adrenal mass associated with a hematoma. The right adrenal gland was resected. Microscopic examination revealed an encapsulated cellular spindle cell proliferation with a prominent inflammatory infiltrate. Immunohistochemically, those spindle cells were diffusely and strongly positive for anaplastic lymphoma kinase-1, and focally and weakly positive for smooth muscle actin. S-100 protein and cytokeratin were negative. The findings were consistent with IMT arising from the adrenal gland. Although IMTs in the adrenal gland are rare, they should be considered in the differential diagnosis of adrenal masses. The clinical behavior of IMTs in general is currently indeterminate and a close clinical follow-up is recommended. The behavior of adrenal IMTs remains uncertain because of rare reported cases and lack of long-term follow-up. Further follow-up of reported cases and recognition of additional new cases is warranted to unmask the true biological behavior of adrenal IMTs.