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.
Misago
Noriyuki
N
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
Satoh
Toshimi
T
Narisawa
Yutaka
Y
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