Author(s) : Osamu MORI, Takashi HASHIMOTO , Department of Dermatology, Kurume University School of Medicine, 67 Asahimachi, Kurume, Fukuoka, 830‐0011, Japan .
Summary : We report the case of a 6‐year‐old Japanese boy with a plexiform fibrohistiocytic tumor on the right perioral region. Clinically, the tumor, 5 mm in diameter, was a solitary, hard, erythematous, slowly growing, painless nodule. There was no preceding trauma. Histology revealed a well‐circumscribed plexiform lesion with a biphasic appearance. Immunohistochemistry demonstrated CD68 positivity in many of mononuclear macrophages. The lesion was negative for S‐100 protein, lysozyme, CD57 and factor XIIIa. Interestingly, the tumor showed an intradermal location from superficial to deep dermis, and lacked osteoclast‐like giant cells. During the follow‐up for 9 months after the resection, there was no recurrence or metastasis.
Keywords : plexiform fibrohistiocytic tumor
Pictures
Figure 1a.A solitary, slowly growing,
painless, mobile nodule below the right ala of a 6-year-old
Japanese boy. The nodule had a nonulcerated, teleangiectatic
surface.
Figure 1b. Low magnification revealed many
tiny cellular nodules that occupy the dermis.
H&E, × 100.
Figure 1c.In some areas isolated nodules
were seen. H&E, × 50.
Figure 1d.Higher magnification showed a
biphasic pattern with spindle-shaped or stellate cells at the
periphery and macrophages in the center of the lesions.
H&E, × 200.
Figure 2a.CD68 immunostain was
positive in macrophages, × 200.
Figure 2b. Smooth muscle actin showed
positive staining in the spindle cells around the
nests. × 200.
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