Orbital melanocytoma.
OBJECTIVE
To report a case of intermediate grade meningeal melanocytoma presenting as a recurrent orbital mass.


BACKGROUND
Melanocytomas are rare, primary, pigmented tumors of the central nervous system, usually presenting as well-circumscribed, encapsulated, solid masses in the posterior cranial fossa and at the spinal region, often attached to the underlying dura. Orbital manifestation is rarely encountered.


METHODS
Case report with computed tomography scan, magnetic resonance imaging, histology, and immunohistochemistry.


RESULTS
A 40-year-old man presented with a recurrent orbital mass manifesting as progressive proptosis of the right eye of 4 years duration. The computed tomography scan and magnetic resonance imaging revealed an intraconal mass in the superior quadrant of the orbit. Histological analysis of the excision biopsy of the mass showed a highly cellular, locally infiltrating melanocytic neoplasm suggestive of an intermediate grade meningeal melanocytoma. Immunohistochemical staining for S-100 protein and HMB-45 monoclonal antibody confirmed the diagnosis.


CONCLUSIONS
Recurrent intermediate grade orbital melanocytomas are rarely encountered and have to be distinguished from other topographically similar primary melanotic tumors. They have to be managed more aggressively if intracranial extension is present due to its close relation to the visual pathways.
Mathai
Alka Mary
AM
Department of Pathology, Kasturba Medical College, Mangalore, Karnataka, India. alka977@gmail.com
Naik
Ramadas
R
Pai
Muktha R
MR
Kini
Jyoti R
JR
Kumar
Suneet
S
Ballal
C K
CK
D000328:Adult; D000951:Antigens, Neoplasm / Q000032:analysis; D014408:Biomarkers, Tumor / Q000032:analysis; D006801:Humans; D008279:Magnetic Resonance Imaging; D008297:Male; D058950:Melanoma-Specific Antigens; D009363:Neoplasm Proteins / Q000032:analysis; D009364:Neoplasm Recurrence, Local; D009508:Nevus, Pigmented / Q000737:chemistry / Q000473:pathology* / Q000601:surgery; D009918:Orbital Neoplasms / Q000737:chemistry / Q000473:pathology* / Q000601:surgery; D009418:S100 Proteins / Q000032:analysis; D014057:Tomography, X-Ray Computed; D014792:Visual Acuity
D000951:Antigens, Neoplasm; D014408:Biomarkers, Tumor; D058950:Melanoma-Specific Antigens; D009363:Neoplasm Proteins; D009418:S100 Proteins