perineurioma

Perineurioma is a rare benign tumor made up of neoplastic perineurial cells [3]. It can be found in soft tissues, intraneurally, or in mucosal sites [4]. Perineuriomas are slowly growing peripheral nerve sheath tumors that are extraordinarily rare in certain areas, such as the sinonasal cavity [7].

There are two main types of perineurioma: intraneural and extraneural. Intraneural perineurioma is a neoplastic proliferation of perineurial cells with unique immunohistochemistry and ultrastructural features [8]. It typically occurs in children and young adults, presenting with motor deficits and muscle atrophy, while sensory deficits are rare at the onset of the disease [13].

Perineuriomas can also be classified into categories such as soft tissue, intraneural, or mucosal sites. They are usually benign and do not recur [6]. The treatment regime for perineurioma is not well established, but it is essential to exclude cases without description of surgical treatment.

Perineuriomas have distinct characteristics, including a layer of connective tissue surrounding bundles of nerve fibers, formed by flattened cells with a basement membrane on each side [10]. They are rare and can be challenging to diagnose. Advances in understanding the clinical presentation, diagnostic imaging, pathologic features, and genetic underpinnings have changed how this pathology is managed.

Perineuriomas can occur over a wide age range, without remarkable gender differences, and most commonly arise on the lower limbs, followed by the upper limbs and trunk [15]. They are very rarely involved in other sites, including viscera.

Perineurioma, a rare benign tumor of the peripheral nerve sheath, can manifest in various ways depending on its location and type. Here are some common signs and symptoms associated with perineurioma:

• Motor deficits: Weakness or loss of function in an arm or leg is a classic presenting symptom, especially in intraneural perineuriomas [7][12].
• Sensory symptoms: Mild sensory symptoms or signs, such as prickling or numbness, are experienced by some patients, although they are less common than motor deficits [5][6].
• Swelling or lump under the skin: A palpable mass or swelling may be present in cases of soft tissue perineuriomas [11].
• Pain, tingling, or numbness: Some patients may experience pain, tingling, or numbness in the affected area [4][9].
• Weakness or loss of function: Gradually progressive weakness and loss of feeling in an arm or leg are common symptoms in intraneural perineuriomas [1].
• Dizziness or loss of balance: In some cases, patients may experience dizziness or a loss of balance due to the tumor's location and impact on surrounding nerves.

It is essential to note that not all perineuriomas cause significant symptoms. Some are found incidentally during medical procedures or imaging studies [10][11]. The signs and symptoms can vary depending on the type and location of the tumor, making diagnosis challenging in some cases [13].

References:

[1] Context result 1 [4] Context result 4 [5] Context result 5 [6] Context result 6 [7] Context result 7 [9] Context result 9 [10] Context result 10 [11] Context result 11 [12] Context result 12 [13] Context result 13

Diagnostic Tests for Perineurioma

Perineurioma, a rare benign nerve sheath tumor, can be challenging to diagnose due to its slow progression and similarity in appearance to other conditions. However, various diagnostic tests can help confirm the diagnosis.

• Imaging Studies: MRI neurography is a key tool in diagnosing perineurioma, allowing for the identification of the tumor and its location within the peripheral nerve fibers [13]. A CT scan can also be used to determine how the tumor may be affecting the surrounding tissues [12].
• Biopsy: Taking a biopsy of an enlarged, nonfunctional fascicle is essential in diagnosing perineurioma. This test helps confirm the presence of perineurial cells and rules out other conditions [8][9].
• Electrophysiological Testing: Electromyogram (EMG) and nerve conduction studies can help assess the functional impact of the tumor on the surrounding nerves [12].
• Histopathological Examination: A biopsy sample is examined under a microscope to confirm the presence of perineurial cells and rule out other conditions. Immunohistochemical profile and ultrastructural studies may also be used in difficult cases [15].

Important Considerations

It's essential to note that a complete resection of the tumor is not recommended, as it can lead to poor results and residual nerve function impairment [7][8]. Instead, a long-distance epineuriotomy to decompress the hypertrophic fascicle may be performed to preserve the nerves' residual function.

References

[7] To diagnose perineurioma, it is essential to take a biopsy of an enlarged, nonfunctional fascicle. Furthermore, a long-distance epineuriotomy to decompress the hypertrophic fascicle is reasonable. To preserve the nerves' residual function, a complete resection is not recommended. Results after grafting are poor.

[8] To diagnose perineurioma, it is essential to take a biopsy of an enlarged, nonfunctional fascicle. Furthermore, a long-distance epineuriotomy to decompress the hypertrophic fascicle is reasonable. To preserve the nerves' residual function, a complete resection is not recommended. Results after grafting are poor.

[12] Jul 19, 2024 — A CT scan can help your provider determine how the tumor may be affecting you. Electromyogram (EMG). For this test, small needles are placed in ...

[13] Intraneural perineurioma is a rare, benign slow-growing lesion arising from the perineurial cells that surrounds the peripheral nerve fibers. Typically it presents during childhood and young adulthood as a motor mononeuropathy. MRI plays an essential role in the diagnosis and localization of the lesion, which appears as a fusiform enlargement of the nerve fascicles that enhances intensely with ...

[15] by RS Macarenco · 2007 · Cited by 142 — The correct diagnosis relies mainly on histologic findings and immunohistochemical profile, but ultrastructural studies can be used in difficult ...

Treatment Options for Perineurioma

Perineurioma, a rare type of peripheral nerve sheath tumor, can be challenging to treat due to its rarity and varying presentation. While surgical resection is often the primary option, drug treatments may also play a role in managing this condition.

• Observation: In some cases, perineuriomas may not require immediate treatment, and observation with regular monitoring may be sufficient (9).
• Laser therapy: Laser therapy has been explored as a potential treatment for perineuriomas, particularly for those that are difficult to access surgically (9).
• Sclerosing agents: Sclerosing agents, such as ethanol or phenol, have been used to treat perineuriomas by injecting them directly into the tumor (9).
• MEK inhibitors: MEK inhibitors, like selumetinib, may be effective in treating certain types of perineuriomas, particularly those associated with neurofibromatosis type 1 (NF1) (8).

Challenges and Limitations

While these drug treatments show promise, it's essential to note that they are not universally applicable and may have varying degrees of success. The effectiveness of these treatments can depend on factors such as the tumor's location, size, and histological characteristics.

• Limited evidence: Currently, there is limited evidence supporting the use of these drug treatments for perineuriomas.
• Individualized treatment plans: Treatment decisions should be made on a case-by-case basis, taking into account the patient's specific needs and circumstances.

Conclusion

In conclusion, while surgical resection remains the primary option for treating perineuriomas, drug treatments may also play a role in managing this condition. Further research is needed to fully understand the effectiveness of these treatments and to develop more targeted and effective therapies for patients with perineuriomas.

References:

• [8]
• [9]

Differential Diagnosis of Perineurioma

Perineurioma, a rare nerve sheath tumor, requires careful differential diagnosis to rule out other neurogenic tumors and soft tissue lesions. The following conditions are often considered in the differential diagnosis of perineurioma:

• Neurofibroma: A benign nerve sheath tumor that is positive for S100 protein, distinguishing it from perineurioma.
• Schwannoma: Another type of nerve sheath tumor that can be confused with perineurioma, but typically has a more distinct capsule and is also positive for S100 protein.
• Low-grade fibromyxoid sarcoma (LGFMS): A rare soft tissue tumor that shares some histological features with perineurioma, but can be distinguished by its characteristic immunoprofile and molecular genetic characteristics.
• Dermatofibrosarcoma protuberans (DFSP): A type of skin cancer that can resemble perineurioma in superficial biopsies, but is negative for EMA and has a distinct histological appearance.
• Cutaneous meningioma: A rare tumor that occurs on the scalp or face, typically positive for SSTR2A and EMA, distinguishing it from perineurioma.

Key Diagnostic Features

To accurately diagnose perineurioma, several key features should be considered:

• Immunohistochemical staining: Perineuriomas are typically positive for claudin-1 and human erythrocyte glucose transporter-1 (hEGT), but negative for EMA.
• Ultrastructural characteristics: The tumor cells in perineurioma have distinct ultrastructural features, including the presence of basement membrane-like structures and perineurial cell processes.

Clinical Implications

Accurate differential diagnosis of perineurioma is crucial to avoid misdiagnosis and inappropriate treatment. Clinicians should be aware of these potential mimics and consider them in the differential diagnosis of patients presenting with nerve sheath tumors or soft tissue lesions.

References:

• [4] Perineuriomas are rare nerve sheath tumors composed of well-differentiated perineurial cells that have a distinct ultrastructural and immunochemical phenotype.
• [10] The differential diagnosis of intraneural perineurioma mainly includes localized reactive Schwann cell proliferations, while that of soft tissue perineurioma includes a variety of soft tissue tumors with fibrous and epithelioid morphologies.
• [12] Folpe et al showed expression of claudin-1 in 11 of 12 cases of perineurioma, highlighting its utility as a diagnostic marker.