NEUROMUSCULAR HAMARTOMA (BENIGN TRITON TUMOR) IN A MOUSE

Histological examination of a 22-month-old CD-1 mouse revealed a three fold enlargement of the right trigeminal ganglion. This change was due to the presence of well-differentiated striated muscle fibers intermi ngling with nerves and ganglion cells. The number of ganglionic SCHWAN N cells was also increased as demonstrated by their positive S-100 pro tein staining. In addition, slight interstitial mononuclear cell infil tration and fibrosis were observed. The myocytes, which stained positi ve for myoglobin and desmin, and the proliferated SCHWANN cells did no t show any signs of cellular or nuclear atypia. The lesion was diagnos ed as ''neuromuscular hamartoma (benign ''Triton'' tumor)'' reflecting the capability of either Schwann cells or neural crest derived precur sor cells to differentiate into various other cell types.