Enjoypath

	IMMUNOHISTOCHEMISTRY
	HMB45: NEGATIVE S100: TUMOR IS INDETERMINATE. MITF: NEGATIVE. MART-1: NEGATIVE. VIMENTIN:: TUMOR IS POSITIVE. TTF-1: TUMOR IS NEGATIVE. CK5/6: TUMOR IS NEGATIVE. CK20: TUMOR IS NEGATIVE. CK7: TUMOR IS NEGATIVE. CD117: NEGATIVE. CD30: NEGATIVE. LCA: NEGATIVE. CD3: NEGATIVE. CK19: NEGATIVE AFP: NEGATIVE. AE 1/3: NEGATIVE. CK8/18: POSITIVE.

	ELECTRON MICROSCOPY
	Ultrastructurally, considerable fixation and processing artifact is apparent. However, the neoplasm consists of sheets of epithelioid like cells in close approximation with each other. Numerous tight junctions are identified. However, the fine architecture of plasma membranes have been destroyed by the paraffin embedding process. The cells appear to have abundant endoplasmic reticulum and throughout these cells there are poorly defined electron dense structures that are the size of melanosomes. These structures lack the unit membrane surrounding them probably because of the fixation artifact. In several of these, there is some suggestion of intercrystalline structure. No villi formation is noted. No glandular formation is noted. (Interpretation performed by Dr. WJH. Performed in the Electron Microscopy Laboratory, Creighton Medical Laboratories, Omaha, NE.) ULTRASTRUCTURAL IMPRESSION: Undifferentiated malignant neoplasm with electron dense core structures, suggestive of melanosomes. COMMENT: The ultrastructural finding suggests that the primary for this neoplasm is a melanoma.