[1833] Orbital Hamartomatous Mesenchymal Lesions in Adults: An Entity To Be Considered

Patricia Jimenez, Javier Fernandez, Clara Delbene, Carme Dinares, Ramon Medel, Santiago Ramon y Cajal, Pere Huguet. Vall Hebron Hospital, Barcelona, Spain

Background: A hamartoma is a tumor-like malformation composed by a disorderly proliferation of mature tissue elements normally present in the organ/anatomical site in which it originates. Neuromuscular hamartoma (NMH) is an infrequent pediatric peripheral-nerve tumor characterized by a proliferation of nerve fibers intermingled with mature muscle fibers in the course of the affected nerve, with clinical manifestations resulting from nerve dysfunction. Rhabdomyomatous mesenchymal hamartoma (RMH) is even rarer, composed of striated muscle fibers randomly arranged in the dermis/subcutaneous tissue, associated with other mesenchymal elements of normal appearance.
Design: Clinical history, histological slides, immuno-studies, imaging techniques and outcome of 3 adult male patients without previous ophthalmic history (ages 61, 62 and 80 years), which debuted with unilateral proptosis due to orbital space-occupying lesions, were reviewed. All biopsies showed a similar histology: a hamartomatous mesenchymal lesion. A fourth case with approximate morphology was discarded because the patient had a history of thyroid orbitopathy and bilateral exophthalmos.
Results: All 3 patients presented with unilateral proptosis and an intermittent orbital discomfort (average evolution of 6.6 months, range 4-10 months), without clinical manifestations of nerve dysfunction. Imaging techniques in all 3 cases showed an unilateral, ill-defined, orbital retrobulbar lesion. Biopsies revealed the morphology of a hamartoma: irregular fibers of skeletal muscle disorderly arranged, intimately intertwined with nerve bundles of variable diameter, mature adipose tissue in varying amounts and vessels of malformative aspect. There was neither cellular atypia nor mitosis. The 3 patients received conservative treatment after diagnosis, without evidence of disease progression by an average of 95 months follow-up.
Conclusions: To our knowledge, these hamartomatous orbital lesions in adults without previous pathology have not been described before. All 3 cases show the typical morphology of a hamartoma, and although they remember to a NMH and/or a RMH, do not meet clearly their characteristics. A clinical course associated with mass effect of the lesion without manifestations of nerve dysfunction suggests that they are not associated with a particular nervous branch. We highlight the importance of consider this diagnosis in a patient with an unilateral orbital space-occupying lesion and the relevancy of biopsy in these cases because these lesions may be managed conservatively and evolution is benign.
Category: Ophthalmic

Wednesday, March 21, 2012 1:00 PM

Poster Session VI # 313, Wednesday Afternoon


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