Oral perineurioma: clinicopathologic features from two cases and review of literature

Clinical Features, Natural History, and Outcomes of Intraneural Perineuriomas: A Systematic Review of the Literature

BACKGROUND

Intraneural perineurioma is a rare peripheral nerve sheath tumor characterized by localized proliferation of perineurial cells. The literature consists predominantly of case reports and institutional series, with inconsistent and confusing nomenclature. We present a pooled analysis of all reported cases of intraneural perineurioma in the literature.

METHODS

A systematic search of PubMed, MEDLINE, Embase, and Scopus was performed according to PRISMA guidelines to identify all reported cases of intraneural perineurioma in the literature. Individual cases were pooled and analyzed for demographics, clinical features, and outcomes.

RESULTS

A total of 172 cases were identified across 72 studies, of which 149 were found in major peripheral nerves and their branches. Median age of patients at diagnosis and onset of symptoms was 18 years (interquartile range [IQR], 12-34 years) years and 13.5 years (IQR, 8-26 years), respectively, with 54.4% (81/149) being female. The most common sites were the sciatic nerve or its branches (41.9%), median nerve (13.5%), radial nerve (12.2%), and brachial plexus (12.2%). Most patients were managed conservatively (52.9%; 72/136). Among those managed conservatively with available follow-up (n = 31), median follow-up was 11 months, and most (67.7%, n = 21) reported no change in neurologic status, although worsening was noted in 29.0% (9/31). Among surgically managed cases (n = 64), the most common intervention was resection with or without repair (62.5%; 40/64), neurolysis (25%; 16/64), or tendon transfers without resection (12.5%; 8/64). No lesion recurred after surgical resection.

CONCLUSIONS

Intraneural perineurioma represents a benign focal lesion presenting with weakness and atrophy affecting adolescents and young adults. Most cases are managed nonoperatively and surgical treatment strategies are varied.

Primary intra-osseous Hybrid Schwannoma-Perineurioma in the mandible

Benign nerve sheath tumours include perineuriomas, schwannomas and neurofibromas. Hybrid schwannoma-perineurioma represents a cutaneous, subcutaneous or occasionally intra-osseous tumour with schwannian cytomorphology and perineurioma-like architecture consisting of a mixture of both types of cells. These tumours can develop at any age and there is no gender-predilection. Tongue is the most frequently affected site, followed by palate, mouth floor, jugal mucosa, lips and, more rarely, mandible. We present a case of hybrid tumour with schwannoma-perineurioma morphology located on the right mandibular body (intra-osseous) of a 54-year-old female patient. The tumour was symptomatic and evolving for six months. Microscopically, it was encapsulated and highly cellularised, presenting fascicular aspect and exhibiting scant mitotic activity. The tumour consisted of distinct cellular populations involving fusiform cells, cells with wavy and hyperchromatic nucleus or even epithelioid cells. Positive immunostaining for S-100 and epithelial membrane antigen (EMA) was observed. The lesion was completely removed under general anaesthesia, with the patient showing no clinical or radiographic sign of relapse after two-year follow-up. Despite the limited knowledge on the pathogenesis of Hybrid Schwannoma-Perineurioma, these tumours seem to present a non-aggressive biological behaviour. Conservative surgery provides adequate solution without recurrence, even after a long-term follow-up. Key words:Nerve sheath tumours, Schwannoma, Perineurioma, Immunohistochemistry.

Storiform collagenoma (sclerotic fibroma) of the oral mucosa

Storiform collagenoma (also called sclerotic fibroma) is uncommon, occurs as a cutaneous fibrous neoplasm, and is particularly rare in mucosal tissue in the head and neck. We describe an unexpected diagnosis in the oral cavity. Histopathological examination showed a proliferation of fibrous tissue, which was well circumscribed but unencapsulated, with thick laminated bundles of eosinophilic collagen that exhibited a storiform or "whorled" pattern. First described by Weary et al in 1972, storiform collagenoma is a marker for Cowden's disease or PTEN hamartoma tumour syndrome. Identification of other synchronous lesions should prompt chromosomal analysis for a mutation in the PTEN gene on chromosome 10q23.

Oral neural tumors: Clinicopathologic analysis of 157 cases and review of the literature

Background

Oral neural tumors (ONTs) are rare lesions and represent reactive or neoplastic proliferations of nerve sheath cells. The purpose of the present study is to report the clinical, demographic and histopathologic features of 157 ONTs diagnosed in a single Oral Pathology Department and review the pertinent literature.

Material and Methods

157 cases of ONTs diagnosed during a 44-year period were retrospectively collected and the diagnosis was reconfirmed by studying representative haematoxylin and eosin stained tissue sections. The patients’ gender and age, as well as the main clinical features of the lesions, were retrieved from the biopsy submission forms.

Results

The 157 ONTs represented approximately 0.4% of 35,590 biopsies accessioned during the study period. They affected 71 male and 86 female patients with a mean age of 38.4±18.8 years. They mainly appeared as asymptomatic nodules of normal or white colour on the tongue, lip mucosa and hard palate. The most common ONT was granular cell tumour (38.9%) followed by neurofibroma (19.7%), schwannoma (15.9%), traumatic neuroma (15.9%), palisaded encapsulated neuroma (8.3%) and nerve sheath myxoma (1.3%).

Conclusions

This study confirmed the rarity of ONTs. Their clinical characteristics mimic other oral lesions; thus, microscopic examination is the only mean to arrive at a definitive diagnosis.

Key words:Oral neural tumors; oral neural neoplasms; neurofibroma; oral neurofibroma; schwannoma; oral schwannoma; neurilemmoma; oral neurilemmoma; granular cell tumor; oral granular cell tumor; traumatic neuroma; oral traumatic neuroma; palisaded encapsulated neuroma; oral palisaded encapsulated neuroma.

Intraosseous intraneural perineurioma derived from the inferior alveolar nerve with an abnormality of chromosome 22 and expression of the BCR-ABL fusion gene: report of a case and review of recent literature

BACKGROUND

Perineurioma (PN) is a peripheral nerve disease that primarily develops in the limbs and trunk and very rarely occurs in the oral cavity. PN is classified into two types: intraneural perineurioma (INPN) and soft tissue perineurioma (extraneural perineurioma, ENPN). In this article, we report a patient with mandibular body INPN derived from the perineurium of the inferior alveolar nerve.

CASE PRESENTATION

The patient was a 43-year-old male. He consulted our department for a detailed examination of the right mandibular body. A biopsy was performed at another hospital and he was diagnosed with a schwannoma. At his first visit, hypesthesia extending from the right lower lip to the mental region was recognized and enlargement of the right mandibular canal was confirmed with X-ray CT and MRI. Considering the possibility of future tumor growth, we extirpated the tumor under general anesthesia. Cystic tumor was seen continuously in the inferior alveolar nerve. Immunohistologically, the tumor cells were positive for Glut-1, weakly positive for EMA, and weakly positive for Claudin-1, and the histopathological diagnosis was INPN. In addition, absence of the BCR region of chromosome 22 and expression of the BCR-ABL fusion gene were observed by fluorescent in situ hybridization (FISH), and a chromosome 22 abnormality was confirmed. These findings indicated that the disease was a neoplastic lesion.

CONCLUSION

Expression of the BCR-ABL fusion gene in INPN that develops in the oral cavity is thought to be very rare, and to the best of our knowledge, ours is the first case to be reported in the literature. About three postoperative years have passed, but findings suggestive of recurrence have not been observed.

Oral peripheral nerve sheath tumors: A clinicopathological and immunohistochemical study of 32 cases in a Brazilian population

Background

Oral peripheral nerve sheath tumors (OPNSTs) are reactive or neoplastic diseases that develop from proliferation of the nerve itself or their limiting sheaths. Here we describe the clinicopathologic data of OPNSTs observed in a sample of the Brazilian population and evaluate the expression of molecules associated with neural biology to determine their usefulness in the diagnosis.

Material and Methods

Descriptive study of cases diagnosed as OPNSTs, from the Pathology Laboratory at the School of Dentistry/ Federal University of Uberlandia, followed by an immunohistochemical study of S-100, CD57, neurofilament protein (NFP) and epithelial membrane antigen (EMA).

Results

OPNSTs comprised 0.27% of all biopsies. There were eight patients with neurofibromas, eight with traumatic neuromas, seven with schwannomas, five with granular cell tumor (GCT), and four with palisaded encapsulated neuromas (PEN). Women were more frequently affected (60.6% of the cases). Tongue and lips prevailed as the most frequent sites. S-100 was reactive in 100% of the cases. Neural fibers evidenced by CD57 reactivity of their Schwann cells were always nested in bundles within neurofibromas and GCT, absent within schwannomas and dispersed within PEN. Reactivity for NFP was limited to axons and then followed the same pattern of CD57, though much less evident. Reactivity for EMA was observed in the capsular tissues and perineurium of nerve fascicles, and absent in parenchymal cells of GCT.

Conclusions

This study showed that OPNSTs are rare, widely benign and often found in tongue and lips. OPNSTs evolve from a common origin to distinct histological patterns, with eventual overlapping in their clinical and morphologic features. The arrangement of reactive residual neural fibers for CD57 can be a useful staining in the differential diagnosis of OPNSTs. Key words:Peripheral nerve sheath tumors. Oral cavity. Differential diagnosis. Immunohistochemistry. CD57 antigens.