Author(s) : M.D.P. Davis, K.R. Harris, F. Earnest IV, L.E. Gibson, Department of Dermatology, Mayo Clinic and Mayo Foundation, 200 First Street SW, Rochester, MN 55905, USA..
Summary : A 41-year-old man presented with intermittent diplopia. Examination revealed mild, left sixth nerve palsy. MRI scan revealed a tumor involving the sphenoid sinus, clivus and cavernous sinus. Transphenoidal exploration and biopsy of the tumor was performed, and histology demonstrated malignant melanoma. Despite resection and radiation therapy, the patient died nine months later. An extensive blue nevus was present on the left side of his scalp, and on surgical exploration this extended intracranially as far as was explored. The histology of the brain lesion and the blue nevus were remarkably similar although cytologically, the brain lesion was more atypical. It was concluded that the brain lesion represented a metastasis or intracranial involvement from the blue nevus. Malignant blue nevus has been previously reported. This case is important because it draws attention to the possibility that extensive lesions involving the scalp may have intracranial involvement and may warrant aggressive management.
Keywords : malignant blue nevus, blue nevus, malignant melanoma.
Pictures
Figure 1. MRI scan. Sagittal T1-weighted image: tumor infiltrates the
clivus producing elevation of the dura (arrow). The bright appearance
of the tumor mass is related to T1 effects of melanin.
Figure 2. Histology of the clivus
tumor. High power view demonstrating pleomorphic and heavily pigmented cellular
infiltrate, consistent with melanoma (hematoxylin-eosin, x 220).
Figure 3. Extensive bluish discoloration
involving left temple, left superior and posterior auricular areas, consistent
with a blue nevus.
Figure 4. Histology of skin biopsy. (A) Pigmented melanocytes
present to the depth of the cutaneous biopsy specimen (hematoxylin-eosin,
x 10). (B) Higher power view of dermis demonstrating spindle-shaped
and pigmented melanocytes, consistent with a blue nevus (hematoxylin-eosin,
x 80).
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