Cellular neurothekeoma with histiocytic differentiation.
BACKGROUND
It is generally accepted that the two types of neurothekeoma (myxoid type and cellular type) represent the two poles of a spectrum. This concept, however, has recently been challenged, and cellular neurothekeomas have been suggested as a separate classification and are included in the "fibrohistiocytic" category by some authors. Cellular neurothekeomas have been reported to show negative immunohistochemical staining for histiocytic markers, and PG-M1 is now considered to be the most reliable histiocytic marker.


METHODS
We report a case of cellular neurothekeoma. The histopathological features in this case were typical for cellular neurothekeoma. Immunohistochemically, the neoplastic cells were diffusely positive for S-100A6 protein, PGP9.5, CD10, CD68 (KP1), PG-M1, and Vimentin, and negative for other antibodies including S-100 protein and factor XIIIa.


CONCLUSIONS
Cellular neurothekeoma expressing both KP-1 and PG-M1 is considered to show histiocytic differentiation, and may be interpreted as a neoplasm with immature nerve sheath differentiation, incidentally expressing histiocytic markers, or as an undifferentiated neoplasm derived from the neural crest cells of nerve sheath/fibrohistiocyte lineage. These results, such as the concomitant expressions of PGP9.5/S-100A6 and PG-M1/CD68 (KP-1), support the theory of multiple differentiation in cellular neurothekeomas. The significance of the expression of CD10 in this cellular neurothekeoma is unclear.
Division of Dermatology, Department of Internal Medicine, Faculty of Medicine, Saga University, Nabeshima 5-1-1, Saga 849-8501, Japan. misago@post.saga-med.ac.jp
Noriyuki
N
Misago
Toshimi
T
Satoh
Yutaka
Y
Narisawa
D000328:Adult; D014408:Biomarkers, Tumor / Q000032:analysis; D002471:Cell Transformation, Neoplastic / Q000737:chemistry / Q000473:pathology*; D005260:Female; D006644:Histiocytes / Q000737:chemistry / Q000473:pathology*; D006801:Humans; D007150:Immunohistochemistry; D018321:Neurothekeoma / Q000737:chemistry / Q000473:pathology* / Q000601:surgery; D012535:Scalp; D012878:Skin Neoplasms / Q000737:chemistry / Q000473:pathology* / Q000601:surgery; D016896:Treatment Outcome
D014408:Biomarkers, Tumor