Orbital involvement in 'sinus' histiocytosis. A report of four cases
D. S. Friendly, R. L. Font and N. A. Rao
Sinus histiocytosis is a newly recognized benign disease affecting mainly
children and young adults and usually having a protracted clinical course
that is relatively unaffected by therapy. This paper describes four
additional patients who had orbital involvement initially and reviews the
salient clinical and histopathologic features of this entity. The
outstanding clinical feature is cervical lymphadenopathy. Associated
findings include low-grade fever, anemia, leukocytosis, and elevated IgG
levels. A small percentage of patients develop proptosis with palpable
orbital tumors. Such patients may not have appreciable lymphadenopathy.
Progressive proptosis may lead to exposure keratitis, corneal ulceration,
endophthalmitis, and loss of the eye. Histopathologically, the lymph nodes
and orbital mass show a proliferation of large histiocytes intermixed with
a variable proportion of lymphocytes and plasma cells. Lymphocytes and
occasionally other cells derived from the hematopoietic system are commonly
seen within the cytoplasm of the histiocytes.
