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Sun M, Shao M, Liu J, Zhao L, Weng Lao I, Yu L, Wang J. Plexiform Cellular Schwannoma in Infancy and Childhood: A Clinicopathological Study of Seven Cases of an Underrecognized Nerve Sheath Tumor with a Tendency Toward Local Recurrence. Int J Surg Pathol 2021; 30:265-272. [PMID: 34696615 DOI: 10.1177/10668969211052236] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022]
Abstract
Plexiform cellular schwannoma (PCS) is very rare, and it is not completely understood. We present our experience with 7 additional cases of PCS in infancy and childhood to further characterize its distinctive clinicopathological features. There were 5 females and 2 males with a mean age of 28 months (ranging, 2 months to 8 years). The involved sites included the left forearm (n = 2), sacrococcygeal region (n = 2), retroperitoneum (n = 1), thoracic spinal canal and thoracic cavity (n = 1), and neck (n = 1). Tumor sizes ranged from 3 to 13 cm in maximum diameter (mean, 7.1 cm). Histologically, all tumors consisted of abundant spindle cells arranged in a multinodular or plexiform growth pattern, possessing elongated, hyperchromatic nuclei and pale eosinophilic cytoplasm with indistinct cell margins. Mitotic figures were easily identified, with a mean count of 4 per 10 consecutive high power fields (HPF). Immunohistochemically, all tumors were strongly and diffusely positive for S100 protein, SOX10 and H3K27me3. The Ki-67 index ranged from 5% to 30% (mean, 15%). Follow-up (available in 6 cases) revealed that 5 patients experienced local recurrence and were treated by re-excision. There was no evidence of recurrence and metastasis in 3 patients, and the other 2 were alive with the disease. In conclusion, PCS is an uncommon nerve sheath tumor predominantly occurring in infants and children, featuring a plexiform or multinodular growth pattern and exhibiting a tendency toward local recurrence. PCS is easily mistaken as malignant peripheral nerve sheath tumor (MPNST) due to its locally aggressive behaviors and worrisome features, including hypercellularity, hyperchromatism and high proliferative activity. Increased awareness of its potential occurrence and greater familiarity with its characteristic features are helpful for both clinicians and pathologists to avoid misdiagnosis and unnecessary overtreatment.
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Affiliation(s)
- Meng Sun
- 89667Fudan University, Shanghai 200032, China.,Institute of Pathology, 89667Fudan University, Shanghai 200032, China
| | - Mengyuan Shao
- 89667Fudan University, Shanghai 200032, China.,Institute of Pathology, 89667Fudan University, Shanghai 200032, China
| | - Jiahan Liu
- 89667Fudan University, Shanghai 200032, China.,Institute of Pathology, 89667Fudan University, Shanghai 200032, China
| | - Lu Zhao
- 89667Fudan University, Shanghai 200032, China.,Institute of Pathology, 89667Fudan University, Shanghai 200032, China
| | - I Weng Lao
- 89667Fudan University, Shanghai 200032, China.,Institute of Pathology, 89667Fudan University, Shanghai 200032, China
| | - Lin Yu
- 89667Fudan University, Shanghai 200032, China.,Institute of Pathology, 89667Fudan University, Shanghai 200032, China
| | - Jian Wang
- 89667Fudan University, Shanghai 200032, China.,Institute of Pathology, 89667Fudan University, Shanghai 200032, China
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Chi AC, Neville BW, Cheng L. Plexiform Schwannoma of the Oral Cavity: Report of Eight Cases and a Review of the Literature. Head Neck Pathol 2020; 15:288-297. [PMID: 32270393 PMCID: PMC8010039 DOI: 10.1007/s12105-020-01159-7] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/26/2020] [Revised: 03/27/2020] [Accepted: 03/30/2020] [Indexed: 12/16/2022]
Abstract
Plexiform schwannoma represents an unusual schwannoma variant, characterized by multinodular growth grossly and/or microscopically. A review of the English-language literature reveals only 28 previously reported cases involving the oral cavity, and herein we present 8 additional cases. Among these 36 patients, the average age at diagnosis was 28 years (range 5 to 62 years), with a female-to-male ratio of 1.4:1. The most frequently involved sites were the tongue (n = 13) and lip (n = 11). Lesion duration prior to presentation averaged 5.3 years (range, 6 weeks to 26 years). The average lesion size was 2.1 cm (range, 0.3 to 16 cm). The typical clinical presentation was a painless mass, although infrequent findings included pain/discomfort, paresthesia, difficulty chewing, and limited buccal mobility. All cases clinically appeared as a solitary mass or localized cluster of tumor nodules, with the exception of one patient who had neurofibromatosis 2 (NF2) and exhibited two distinct nodules on the tongue and buccal mucosa. In addition, extraoral neural neoplasms were evident in four patients, including three with NF2. Typical microscopic findings included multiple well-circumscribed tumor nodules, each surrounded by a perineurium-derived capsule with immunoreactivity for epithelial membrane antigen. The nodules contained characteristically bland and diffusely S-100-positive spindle cells arranged in Antoni A and B patterns; however, modest nuclear pleomorphism was evident in three cases. Most patients (n = 23) were treated by excision or enucleation and curettage, and three patients experienced recurrence. Unlike plexiform neurofibromas, plexiform schwannomas exhibit only a weak association with neurofibromatosis and have no known malignant potential.
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Affiliation(s)
- Angela C. Chi
- Division of Oral Pathology, College of Dental Medicine, Medical University of South Carolina, 173 Ashley Ave., MSC 507, Charleston, SC 29425 USA
| | - Brad W. Neville
- Division of Oral Pathology, College of Dental Medicine, Medical University of South Carolina, 173 Ashley Ave., MSC 507, Charleston, SC 29425 USA
| | - Lisa Cheng
- Department of Diagnostic Sciences, Texas A&M University College of Dentistry, Dallas, USA
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Flucke U, van Noesel MM, Wijnen M, Zhang L, Chen CL, Sung YS, Antonescu CR. TFG-MET fusion in an infantile spindle cell sarcoma with neural features. Genes Chromosomes Cancer 2017; 56:663-667. [PMID: 28510278 DOI: 10.1002/gcc.22470] [Citation(s) in RCA: 51] [Impact Index Per Article: 7.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/02/2017] [Revised: 05/04/2017] [Accepted: 05/05/2017] [Indexed: 12/21/2022] Open
Abstract
An increasing number of congenital and infantile sarcomas displaying a primitive, monomorphic spindle cell phenotype have been characterized to harbor recurrent gene fusions, including infantile fibrosarcoma and congenital spindle cell rhabdomyosarcoma. Here, we report an unusual spindle cell sarcoma presenting as a large and infiltrative pelvic soft tissue mass in a 4-month-old girl, which revealed a novel TFG-MET gene fusion by whole transcriptome RNA sequencing. The tumor resembled the morphology of an infantile fibrosarcoma with both fascicular and patternless growth, however, it expressed strong S100 protein immunoreactivity, while lacking SOX10 staining and retaining H3K27me3 expression. Although this immunoprofile suggested partial neural/neuroectodermal differentiation, overall features were unusual and did not fit into any known tumor types (cellular schwannoma, MPNST), raising the possibility of a novel pathologic entity. The TFG-MET gene fusion expands the genetic spectrum implicated in the pathogenesis of congenital spindle cell sarcomas, with yet another example of kinase oncogenic activation through chromosomal translocation. The discovery of this new fusion is significant since the resulting MET activation can potentially be inhibited by targeted therapy, as MET inhibitors are presently available in clinical trials.
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Affiliation(s)
- Uta Flucke
- Department of Pathology, Radboud University Medical Centre, Nijmegen, The Netherlands
| | - Max M van Noesel
- Princess Máxima Center for Pediatric Oncology, Utrecht, The Netherlands
| | - Marc Wijnen
- Princess Máxima Center for Pediatric Oncology, Utrecht, The Netherlands
| | - Lei Zhang
- Department of Pathology, Memorial Sloan Kettering Cancer Center, New York, New York
| | - Chun-Liang Chen
- Department of Pathology, Memorial Sloan Kettering Cancer Center, New York, New York
| | - Yun-Shao Sung
- Department of Pathology, Memorial Sloan Kettering Cancer Center, New York, New York
| | - Cristina R Antonescu
- Department of Pathology, Memorial Sloan Kettering Cancer Center, New York, New York
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Luzar B, Tanaka M, Schneider J, Calonje E. Cutaneous microcystic/reticular schwannoma: a poorly recognized entity. J Cutan Pathol 2015; 43:93-100. [PMID: 26350054 DOI: 10.1111/cup.12624] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/20/2015] [Revised: 07/19/2015] [Accepted: 08/02/2015] [Indexed: 12/22/2022]
Abstract
BACKGROUND Microcystic/ reticular schwannoma is exceptionally rare yet distinctive morphological variant of schwannoma with predilection for visceral sites lacking association with neurofibromatosis. AIMS To further delineate clinicopathological features of cutaneous microcystic/reticular schwannoma and to discuss its differential diagnosis. RESULTS We analyzed three cutaneous microcystic/reticular schwannomas, occurring in two males and one female (mean age: 37.6 years). The tumors presented as a non-painful slightly raised papule (mean: 0.7 cm) on upper arm (n = 2) and back (n = 1). No recurrences were observed despite marginal excision (mean follow up: 42 months). Histopathologically, a multilobular proliferation was present in the dermis composed of bland tumor cells forming distinctive microcystic, reticular, lace-like or pseudoglandular structures, containing abundant myxoid/mucinous material. By immunohistochemistry, tumor cells lining microcystic structures corresponded to Schwann cells (diffuse S100 positive, variable GFAP positivity). A discontinuous EMA-positive perineurium was present at the periphery of some of the lobules. CONCLUSION Cutaneous microcystic/reticular schwannoma expands the spectrum of benign peripheral nerve sheath tumors with reticular morphology encountered in the skin. Other tumors in this group include reticular perineurioma and hybrid tumors with reticular morphology, e.g. reticular perineurioma/schwannoma and reticular perineurioma/neurofibroma.
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Affiliation(s)
- Boštjan Luzar
- Institute of Pathology, Medical Faculty University of Ljubljana, Ljubljana, Slovenia
| | - Maiko Tanaka
- Department of Dermatology, Graduate School of Biomedical Sciences, Hiroshima University, Hiroshima, Japan
| | - Johann Schneider
- Division of Anatomical Pathology at University of Stellenbosch, Cape Town, South Africa
| | - Eduardo Calonje
- Department of Dermatopathology, St John's Institute of Dermatology, St Thomas' Hospital, London, UK
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