Sino-orbital chloroma presenting as unilateral proptosis in a boy.

Granulocytic sarcoma or chloroma is an unusual localized tumor composed of cells of myeloid origin. Involvement of the orbit and the ethmoid sinuses and presenting as proptosis is rare. Diagnosis could be difficult and delayed when there are no other systemic manifestations, especially with normal peripheral blood and bone marrow picture. We present one such case with unilateral proptosis as the sole presenting sign that posed a diagnostic challenge to us. Orbital decompression by an otolaryngologist may have a role in managing such a case.