[502] Extra-Acral Cutaneous/Soft Tissue Sclerosing Perineuriomas: An Underrecognized Entity in the Differential of CD34 Positive Cutaneous Neoplasms

MD Fox, BC Gleason, AB Thomas, TL Cibull. NorthShore University HealthSystem, Evanston, IL; Diagnostic Pathology Group, Sacramento, CA

Background: Perineuriomas are an uncommon group of tumors composed of perineurial cells of peripheral nerve sheath derivation. They have been further classified as soft tissue, intraneural, sclerosing, and reticular variants; each having distinct immunohistochemical and ultrastructural properties. Sclerosing perineuriomas have been reported to occur almost exclusively on the hands of young men. Histologically the cells are arranged in cords, trabeculae, and chains within a densely sclerotic stroma and the nuclei vary from spindled to round. We describe three examples of cutaneous/soft tissue sclerosing perineuriomas with extra-acral involvement.
Design: We recently encountered three extra-acral cutaneous/soft tissue perineuromas which demonstrated prominent sclerotic change. Each case was evaluated for the amount of sclerotic change, which was further classified as focal or diffuse. Additionally, all three cases were characterized immunohistochemically for expression of EMA, CD34, and S-100.
Results:

Immunohistochemical and histologic findings in extra-acral sclerotic perineuriomas

SITE	AGE	EMA	CD34	S-100	SCLEROSIS	CYTOLOGY
Forearm	46	+ (focal)	+ (diffuse)	-	+ (focal)	Epithelioid/Spindle
Lower lateral leg	60	+ (diffuse)	+ (diffuse)	-	+ (diffuse)	Spindle
Upper lip	84	+ (diffuse)	+ (diffuse)	-	+ (diffuse)	Spindle

Focal >25% to <75%, Diffuse >75%


Conclusions: Recent reports have described the sclerosing variant of perineuriomas as having a predilection for acral regions. Our data demonstrates that perineuriomas with significant sclerotic change also occur in extra-acral locations. Additionally, it is important to recognize that perineuriomas can demonstrate a strong diffuse expression of CD34 and thus should not be confused with other CD34 positive cutaneous spindle to epithelioid cell proliferations. We suggest that when encountering cutaneous spindle to epithelioid cell proliferations that expresses CD34; and extra-acral sclerosing neoplasms, an EMA stain should be considered to aid in the diagnosis of extra-acral sclerotic perineuriomas.
Category: Dermatopathology

Monday, March 22, 2010 9:30 AM

Poster Session I Stowell-Orbison/Surgical Pathology/Autopsy Awards Poster Session # 64, Monday Morning