Peripheral Nerve Sheath Tumors Resembling Human Atypical Neurofibroma in Goldfish (Carassius auratus, Linnaeus, 1758)

Skin spindle cell tumors (SSTs) frequently occur in fishes, with peripheral nerve sheath tumors (PNSTs) being the most commonly reported neoplasms in goldfish. However, distinguishing PNSTs from other SCTs is not always possible when relying exclusively on routine cytological and histopathological findings. Therefore, the aim of this study is to characterize six skin nodules, resembling atypical neurofibromas in humans, found in six cohabiting goldfish (Carassius auratus), and to determine a minimal subset of special stains required to correctly identify PNSTs in this species. Routine cytology and histopathology were indicative of an SCT with nuclear atypia in all cases, with randomly distributed areas of hypercellularity and loss of neurofibroma architecture. Muscular and fibroblastic tumors were excluded using Azan trichrome staining. Alcian blue and Gomori’s reticulin stains revealed the presence of intratumoral areas of glycosaminoglycans or mucins and basement membrane fragments, respectively. PAS and PAS–diastase stains confirmed the latter finding and revealed intra- and extracellular glycogen granules. Immunohistochemistry displayed multifocal, randomly distributed aggregates of neoplastic cells positive for S100 protein and CNPase, intermingled with phosphorylated and non-phosphorylated neurofilament-positive axons. Collectively, these findings are consistent with a PNST resembling atypical neurofibroma in humans, an entity not previously reported in goldfish, and suggest that Azan trichrome staining, reticulin staining, and immunohistochemistry for S100 protein and CNPase represent a useful set of special stains to identify and characterize PNSTs in this species.

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Peripheral nerve sheath tumors in goldfish (Carassius auratus) similar to human atypical neurofibroma

10.1055/s-0041-1729391 ◽

2021 ◽

Author(s):

F Armando ◽

C Pigoli ◽

M Gambini ◽

A Ghidelli ◽

G Ghisleni ◽

...

Keyword(s):

Peripheral Nerve ◽

Carassius Auratus ◽

Nerve Sheath Tumors ◽

Peripheral Nerve Sheath Tumors ◽

Goldfish Carassius Auratus ◽

Nerve Sheath ◽

Atypical Neurofibroma

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Multifocal cutaneous peripheral nerve sheath tumors in a goldfish, Carassius auratus (L.)

Journal of Exotic Pet Medicine ◽

10.1053/j.jepm.2019.10.002 ◽

2019 ◽

Author(s):

Alessio Arbuatti ◽

Sabrina Vanessa Patrizia Defourny ◽

Leonardo Della Salda ◽

Mariarita Romanucci

Keyword(s):

Peripheral Nerve ◽

Carassius Auratus ◽

Nerve Sheath Tumors ◽

Peripheral Nerve Sheath Tumors ◽

Goldfish Carassius Auratus ◽

Nerve Sheath

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Tyrosinase Expression in Malignant Melanoma, Desmoplastic Melanoma, and Peripheral Nerve Tumors

Archives of Pathology & Laboratory Medicine ◽

10.5858/2002-126-0816-teimmd ◽

2002 ◽

Vol 126 (7) ◽

pp. 816-822 ◽

Cited By ~ 6

Author(s):

Jenny L. Boyle ◽

Helen M. Haupt ◽

Jere B. Stern ◽

Hinke A. B. Multhaupt

Keyword(s):

Peripheral Nerve ◽

S100 Protein ◽

Dermatofibrosarcoma Protuberans ◽

Antigen Retrieval ◽

Nerve Sheath Tumors ◽

Peripheral Nerve Sheath Tumors ◽

Desmoplastic Melanoma ◽

Nerve Sheath ◽

Tyrosinase Expression ◽

Hmb 45

Abstract Context.—Pathologists may encounter problems in the differential diagnosis of malignant melanoma, spindle and epithelioid neoplasms of peripheral nerves, and fibrohistiocytic tumors. Tyrosinase has been demonstrated to be a sensitive marker for melanoma. Objective.—To determine the specificity of tyrosinase expression in the differential diagnosis of melanoma, desmoplastic melanoma, and peripheral nerve sheath tumors. Design.—Immunoreactivity for tyrosinase, HMB-45 (anti-gp100 protein), S100 protein, CD34, and vimentin was studied in 70 tumors, including 15 melanomas (5 desmoplastic, 4 amelanotic, 6 melanotic), 13 malignant peripheral nerve sheath tumors; 10 schwannomas (1 pigmented), 12 neurofibromas (4 pigmented), and 20 fibrohistiocytic tumors (10 dermatofibrosarcoma protuberans and 10 dermatofibromas). Microwave-based antigen retrieval was performed in 10mM citrate buffer, pH 6.0, for 20 minutes at 121°C. Results.—All melanomas demonstrated positive immunostaining for tyrosinase, HMB-45, and S100 protein. Immunoreactivity for HMB-45 was generally stronger than that for tyrosinase in amelanotic lesions and significantly stronger in 1 of the desmoplastic lesions. The 4 pigmented neurofibromas were focally positive for tyrosinase, but did not stain for HMB-45. The pigmented schwannoma was focally positive for both tyrosinase and HMB-45. The malignant peripheral nerve sheath tumors, dermatofibrosarcoma protuberans, and dermatofibromas were nonreactive for tyrosinase and HMB-45. Conclusions.—Our results support the sensitivity of tyrosinase expression and demonstrate the relative specificity of tyrosinase as a marker for melanocytic lesions, including desmoplastic melanoma, although pigmented peripheral nerve tumors may demonstrate focal positive staining. Immunoreactivity for tyrosinase and HMB-45 may have been enhanced by the microwave-based antigen-retrieval technique used in this study.

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Expression of Protein Gene Product 9.5 in Epithelioid and Conventional Malignant Peripheral Nerve Sheath Tumors

Archives of Pathology & Laboratory Medicine ◽

10.5858/2001-125-1321-eopgpi ◽

2001 ◽

Vol 125 (10) ◽

pp. 1321-1325

Author(s):

Mai P. Hoang ◽

Prasanna Sinkre ◽

Jorge Albores-Saavedra

Keyword(s):

Peripheral Nerve ◽

Protein Gene ◽

S100 Protein ◽

Dermatofibrosarcoma Protuberans ◽

Protein Gene Product 9.5 ◽

Nerve Sheath Tumors ◽

Protein Gene Product ◽

Peripheral Nerve Sheath Tumors ◽

Nerve Sheath ◽

Synovial Sarcomas

Abstract Context.—Due to the frequent lack of S100 protein expression in malignant peripheral nerve sheath tumors (MPNSTs), especially the epithelioid variant, these tumors are difficult to diagnose without the aid of electron microscopy or a clinical history of neurofibromatosis. Methods.—Protein gene product 9.5 (PGP9.5), a broad neural marker, is expressed in nerve fibers and neurons of both the peripheral and central nervous systems. We compared its expression to that of S100 protein in 16 cases of MPNST. As controls, 6 monophasic synovial sarcomas, 9 leiomyosarcomas, and 5 dermatofibrosarcoma protuberans were included. Results.—Expression of PGP9.5 was seen in 15 MPNSTs, with 3 to 4+ positivity in the majority of the cases. Ten cases, 2 epithelioid and 8 conventional MPNSTs, were reactive with PGP9.5, but were negative for S100 protein. Five cases were immunoreactive for both S100 protein and PGP9.5. One case was negative for PGP9.5 but demonstrated focal S100 protein positivity. Expression of PGP9.5 was seen in 4 of 6 synovial sarcomas, 3 of 9 leiomyosarcomas, and none of 5 dermatofibrosarcoma protuberans. Conclusion.—Although PGP9.5 is not a specific marker for MPNST, it is a more sensitive marker than S100 protein (94% vs 38%). When there is a lack of S100 protein expression and a broad panel of immunostains, such as cytokeratin, epithelial membrane antigen, and smooth muscle actin, yields only focal or equivocal staining, PGP9.5 is a useful diagnostic adjunct in confirming the neural origin of a spindle cell sarcoma.

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