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Figure 1.
Histological section stained with hematoxylin-eosin. A, Squamous epithelium with subepithelial spindle cell proliferation with an interweaving fascicular pattern (original magnification ×40). B, Hypercellular areas and mild cellular atypia (original magnification ×200). C, The nuclei of neoplastic cells have an elongated, spindle-shaped, wavy profile with long, slender, bipolar, eosinophilic cytoplasmic processes (original magnification ×400). D, Mitotic figure (arrow) (original magnification ×400).

Histological section stained with hematoxylin-eosin. A, Squamous epithelium with subepithelial spindle cell proliferation with an interweaving fascicular pattern (original magnification ×40). B, Hypercellular areas and mild cellular atypia (original magnification ×200). C, The nuclei of neoplastic cells have an elongated, spindle-shaped, wavy profile with long, slender, bipolar, eosinophilic cytoplasmic processes (original magnification ×400). D, Mitotic figure (arrow) (original magnification ×400).

Figure 2.
Immunohistochemical results. Tumor cells stained positive for epithelial membrane antigen (original magnification ×400) (A), glucose transporter protein 1 (GLUT-1) (original magnification ×200) (B), and protein gene product 9.5 (original magnification ×200) (C) and negative for CD34 (positive in reactive vessels) (original magnification ×40) (D).

Immunohistochemical results. Tumor cells stained positive for epithelial membrane antigen (original magnification ×400) (A), glucose transporter protein 1 (GLUT-1) (original magnification ×200) (B), and protein gene product 9.5 (original magnification ×200) (C) and negative for CD34 (positive in reactive vessels) (original magnification ×40) (D).

1.
Hornick  JLFletcher  C Soft tissue perineurioma: clinicopathologic analysis of 81 cases including those with atypical histologic features. Am J Surg Pathol 2005;29 (7) 845- 858
PubMedArticle
2.
Suster  DPlaza  JAShen  R Low-grade malignant perineurioma (perineurial sarcoma) of soft tissue: a potential diagnostic pitfall on fine needle aspiration. Ann Diagn Pathol 2005;9 (4) 197- 201
PubMedArticle
3.
Ortiz-Hidalgo  CCarvajal-Dosamantes  A Perineuroma maligno (tumor maligno de vaina nerviosa periférica, perineural): estudio inmunohistoquímico de un tumor poco frecuente, utilizando EMA, GLUT-1 y Claudina-1, como marcadores de diferenciación perineural. Rev Esp Patol 2006;39 (2) 105- 111
4.
Piña-Oviedo  SOrtiz-Hidalgo  C The normal and neoplastic perineurium: a review. Adv Anat Pathol 2008;15 (3) 147- 164
PubMedArticle
5.
Macarenco  RSEllinger  FOliveira  AM Perineurioma: a distinctive and underrecognized peripheral nerve sheath neoplasm. Arch Pathol Lab Med 2007;131 (4) 625- 636
PubMed
6.
Hirose  TTani  TShimada  TIshizawa  KShimada  SSano  T Immunohistochemical demonstration of EMA/Glut1-positive perineurial cells and CD34-positive fibroblastic cells in peripheral nerve sheath tumors. Mod Pathol 2003;16 (4) 293- 298
PubMedArticle
Research Letters
August 2009

Soft-Tissue Perineurioma of the Bulbar Conjunctiva

Arch Ophthalmol. 2009;127(8):1058-1060. doi:10.1001/archophthalmol.2009.167

Perineuriomas are rare peripheral nerve sheath tumors composed exclusively of neoplastic perineurial cells and showing distinctive morphologic, ultrastructural, and immunophenotypic features that distinguish them from other nerve sheath tumors. Perineuriomas can be broadly divided into 2 histological categories: an intraneural group and a more common extraneural or soft-tissue group.1 Most of these neoplasms are benign, but perineuriomas of low-grade malignant potential and malignant form have also been reported.2,3 Soft-tissue perineurioma clinically manifests as a painless nodule, occurs mostly in superficial soft tissue, and only infrequently affects deep soft tissue of the extremities or trunk. Rare examples arising at visceral locations have been reported.4,5 There are no reported cases in the English-language literature of perineuriomas affecting the conjunctiva.

Report of a Case

A 47-year-old man had a painless, slowly growing mass in the right bulbar conjunctiva since 3 months before admission. He underwent surgical removal of a 1.0-cm nodule. Grossly, the specimen consisted of tissue fragments with aggregated dimensions of 1.0 × 0.8 × 0.3 cm that were brownish and firm. Microscopical examination revealed a nonencapsulated subepithelial spindle cell proliferation composed of elongated cells with wavy nuclei and long, slender, eosinophilic cytoplasmic processes. The tumor cells showed an interweaving fascicular growth pattern and focal storiform arrangement, with hypercellular areas and mild cytologic atypia. There were 7 mitotic figures per 10 high-power fields and no necrosis (Figure 1). Immunohistochemical studies showed reactivity for epithelial membrane antigen (EMA) (titer, 1:150 [Dako Corp, Glostrup, Denmark]; antigen retrieval titer, 1:20 [Trilogy; Cell Marque Corp, Rocklin, California] for 40 minutes with heating at 95°C), glucose transporter protein 1 (GLUT-1) (titer, 1:200 [Cell Marque Corp]), and protein gene product 9.5 (titer, 1:100 [Neomarkers Inc, Fremont, California]); showed reactivity focally for claudin-1 (prediluted [Dako Corp]) and collagen IV (titer, 1:100 [Biogenex, Andhra Pradesh, India]); and showed negative results for AE1/3 (titer, 1:50 [Cell Marque Corp]), actin (titer, 1:30 [Cell Marque Corp]), CD34 (titer, 1:100 [Dako Corp]), and S-100 protein (titer, 1:4000 [Bio SB, Inc, Santa Barbara, California]). Ki-67 (titer, 1:25 [Cell Marque Corp]) labeled approximately 10% of the neoplastic cells (Figure 2). Based on the morphologic and immunohistochemical findings, the diagnosis of a perineurioma with atypical histological features in the bulbar conjunctiva was made. After the resection, the patient was lost to follow-up.

Comment

Although perineurial cell proliferation may be suspected histologically with routine hematoxylin-eosin staining, a definite identification needs the demonstration of perineurial cell features using immunohistochemical studies. The morphologic criteria include spindle cells with curved or wavy thin nuclei and thin, elongated cytoplasmic processes, arranged in lamellae, and a storiform growth pattern forming loose whorls and bundles. By immunohistochemistry, perineurial cells stain positive for EMA, GLUT-1, and claudin-1; may stain positive for protein gene product 9.5 and CD34; and stain negative for S-100 protein, CD57, and neurofilaments.6

Perineuriomas are benign soft-tissue neoplasms, but atypical and malignant examples have been reported.1,3,4 According to Hornick and Fletcher,1 cases with atypical pleomorphic cytologic results that show abrupt transition from typical cytomorphologic findings and storiform architecture to markedly hypercellular areas with a fascicular growth pattern and diffuse infiltration of adjacent skeletal muscle have been classified as atypical perineuriomas. Hornick and Fletcher also state that the mitotic count is variable. These histological features have no clinical significance and may be comparable to the degenerative changes observed in ancient schwannoma.1 In benign and atypical forms of perineurioma, surgical resection with free margins is curative; only 5% of cases have shown recurrence, and there are no reported cases with metastases.1,4,5

The differential diagnosis of soft-tissue perineurioma includes cellular schwannoma (S-100 protein +; CD34 +/−; EMA −), low-grade fibromyxoid sarcoma of Evans (S-100 protein −; EMA +/−; CD34 −), solitary fibrous tumor (CD34 +; S-100 protein −; EMA −), and benign fibrous histiocytoma or low-grade malignant fibrous histiocytoma (CD34 −; S-100 protein −; EMA −; CD68 +). Immunohistochemical studies will help separate these 4 entities.16

To our knowledge, this is the first case of atypical perineurioma arising in the bulbar conjunctiva reported in the English-language literature.

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Article Information

Correspondence: Dr Ortiz-Hidalgo, Department of Pathology, The American British Cowdray Medical Center, Sur 136 No. 116, Col Las Americas, Mexico DF 01120, Mexico (cortiz@abchospital.com).

Financial Disclosure: None reported.

References
1.
Hornick  JLFletcher  C Soft tissue perineurioma: clinicopathologic analysis of 81 cases including those with atypical histologic features. Am J Surg Pathol 2005;29 (7) 845- 858
PubMedArticle
2.
Suster  DPlaza  JAShen  R Low-grade malignant perineurioma (perineurial sarcoma) of soft tissue: a potential diagnostic pitfall on fine needle aspiration. Ann Diagn Pathol 2005;9 (4) 197- 201
PubMedArticle
3.
Ortiz-Hidalgo  CCarvajal-Dosamantes  A Perineuroma maligno (tumor maligno de vaina nerviosa periférica, perineural): estudio inmunohistoquímico de un tumor poco frecuente, utilizando EMA, GLUT-1 y Claudina-1, como marcadores de diferenciación perineural. Rev Esp Patol 2006;39 (2) 105- 111
4.
Piña-Oviedo  SOrtiz-Hidalgo  C The normal and neoplastic perineurium: a review. Adv Anat Pathol 2008;15 (3) 147- 164
PubMedArticle
5.
Macarenco  RSEllinger  FOliveira  AM Perineurioma: a distinctive and underrecognized peripheral nerve sheath neoplasm. Arch Pathol Lab Med 2007;131 (4) 625- 636
PubMed
6.
Hirose  TTani  TShimada  TIshizawa  KShimada  SSano  T Immunohistochemical demonstration of EMA/Glut1-positive perineurial cells and CD34-positive fibroblastic cells in peripheral nerve sheath tumors. Mod Pathol 2003;16 (4) 293- 298
PubMedArticle
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