Schwannoma of the superficial peroneal nerve presenting as web space pain

Ancient Schwannoma Along the Patellar Tendon: Unveiling a Rare Clinical Phenomenon With Literature Review

Ancient schwannoma, a rare subtype of schwannoma, a benign tumor originating from nerve sheaths, can arise from various nerves, except for the optic, olfactory, spinal, and autonomic nervous systems. Schwannomas are typically characterized by the presence of neoplastic Schwann cells and tend to develop eccentrically. Malignant transformations of schwannomas are exceptionally uncommon. In this case report, a 42-year-old male presented with a painful lump on the front of his left knee. The lump was described as an extra-articular swelling below the kneecap, situated over the patellar tendon. Initially, ultrasonography (USG) indicated the presence of a slow-flow vascular malformation in the infrapatellar region of the left knee. However, subsequent magnetic resonance imaging (MRI) revealed a well-defined mass in the subcutaneous plane below the knee, with minimal septations, leading to an initial suspicion of a large sebaceous cyst. Further investigation through histopathological analysis confirmed the diagnosis of an extra-articular schwannoma. This finding highlights the importance of thorough examination and diagnostic techniques in differentiating between various types of soft tissue masses. Schwannomas, although uncommon in certain locations, should be considered in the differential diagnosis of painful lumps, even in atypical anatomical sites such as the knee.

Schwannoma: A Rare Hoffa's Fat Pad Tumor

Hoffa's fat pad can be affected by a variety of tumors. Schwannomas are benign and typically solitary neoplasms of the peripheral nerve sheath; they are made up of the neoplastic Schwann cells and are usually located eccentrically. Malignant schwannomas are extremely uncommon. Here we report a case of an intra-articular schwannoma of the knee. A 54-year-old man presented with a painful lump in the medial aspect of the knee. Magnetic resonance imaging revealed a well-circumscribed intra-articular mass, which was later diagnosed as an intra-articular schwannoma based on biopsy findings.

Intramural schwannoma involving a vein

Schwannoma involving the blood vessels is a rare phenomenon. So far, only three cases of intravascular schwannoma have been described (all of which were intraluminal), and the origin of the schwannoma in such cases is not yet completely understood. Here, we describe a very rare intramural venous schwannoma in the subcutaneous right prepatellar area of a 31-year-old man. The schwannoma grew by enlarging and thickening the blood vessel wall, between two preserved layers of the vein. In some areas, there was erosion of the luminal layer, with fibrin apposed to the tumor. The tumor expressed S100 and was negative for CD31, CD34, desmin, and smooth muscle actin. The expression of p16 was preserved. Endothelial markers such as CD31 and Factor VIII showed the endothelial lining (which was D2-40-negative) above the tumor. Although degenerative atypia was present, there were no mitotic figures or necrosis identified.

A Case of Schwannoma of the Common Peroneal Nerve in the Knee

Schwannomas are benign neurogenic tumors of peripheral nerves that originate from neural sheath. The aim of this case report is to bring to mind the schwannoma in the patient with knee pain. A 39-year-old woman presented with a complaint of knee pain of three months history. After surgical intervention, the patient’s complaints completely disappeared in the post-operative period. This should come to mind in the differential diagnosis of knee pain.

Ancient Schwannoma of superficial peroneal nerve presenting as intermittent leg pain: A case report

INTRODUCTION

Schwannomas are benign, encapsulated, slow-growing and usually solitary tumors originating from Schwann cells of the peripheral nerve sheath. Schwannomas of the superficial peroneal nerves are very rare, and therefore scarcely documented in the literature. The authors report a case of a diagnosed superficial fibular nerve sheath tumor with an unreported clinical presentation.

PRESENTATION OF CASE

A 52-year-old Caucasian female arrived to our Orthopedics Department complaining of pain and numbness of the lateral aspect of her left leg. These symptoms were present for a year and were more evident at the end of the day, or after a long time in the orthostatic position. No evidence of other medical illnesses was found. There was no record of prior traumatic events related to that limb. Diagnosis of a benign peripheral nerve tumor was achieved and the patient was treated by surgical excision of the lesion.

DISCUSSION

The intermittent symptomatology presentation on this case suggest a mechanical compression etiology, allied to classical pain and paresthesia often exhibited by this kind of the tumor. An intracompartimental pressure elevation could explain why the symptoms disclosed an episodic pattern, due to a constricted, inclosed nerve.

CONCLUSION

We describe a rare case of a patient with an unusual superficial peroneal nerve Schwannoma clinical presentation. Literature on this topic is scarce and, therefore, this case report intends to add further data about this kind of lesion.

Tarsal tunnel syndrome secondary to schwannoma of the posterior tibial nerve

Schwannoma is a benign tumor that arises from the peripheral nerve sheath. It presents as a discrete, often tender, and palpable nodule associated with neurogenic pain or paresthesia when compressed or traumatized. The growth rate is usually slow, and these lesions seldom exceed 2 cm in diameter. We report the case of a large schwannoma arising from the posterior tibial nerve located in the posterior medial ankle. The core needle biopsy findings were suggestive of a schwannoma, with spindle cells strongly and uniformly immunostaining for S-100 protein. The mass was marginally excised. The surgical specimen consisted of a grossly encapsulated white-yellow mass with irregular contours, measuring 3.7 × 3.5 × 2.7 cm. The cut surface showed areas of pin-point hemorrhage. The patient did not encounter any motor deficits; however, early results showed some subjective numbness. Few reports have been published of schwannomas arising from the tibial nerve. Marginal excision appears to be the recommended therapy for this tumor, without any evidence of recurrence at 9 months of follow-up.

Foot schwannomas that mimic nerve-entrapment syndromes: a report of three cases

Schwannomas of the foot are rare. We describe three cases that mimicked compressive neuropathy, two resembling tarsal tunnel syndrome and a third resembling Morton's neuroma. All three patients had complete resolution of their pain after resection of the tumor.

Sciatica in a patient with unusual peripheral nerve sheath tumors

BACKGROUND

Other causes such as peripheral schwannomas can mimic lumbar disk disease.

CASE DESCRIPTION

We present an unusual case of multiple nerve sheath tumors in a patient with left radicular leg pain accompanied by a Tinel sign. Initial lumbar MR imaging revealed a mass in the right lumbar plexus, side opposite the patient's symptoms. Magnetic resonance neurography subsequently revealed a compressive mass of the sciatic nerve proximal to the popliteal fossa, histologically identified as a schwannoma.

CONCLUSION

This case emphasizes the importance of continued investigation when the radiographic findings do not correlate with the patient's history in the presence of localizing signs on physical examination.

Superficial peroneal nerve anatomic variability changes surgical technique

Entrapment of the superficial peroneal nerve is an uncommon entrapment that occurs in sports trauma or fracture and dislocation as the nerve comes under pressure between the underlying muscles and the overlying fascia. Although the superficial peroneal nerve traditionally is depicted as being in the lateral compartment, we have found it in the anterior compartment in some patients. We hypothesized that patients with entrapment of the superficial peroneal nerve were more likely to have this anatomic variant than the normal population and that surgical decompression of both compartments would improve clinical outcome versus the historic surgical approach of decompressing just the lateral compartment. We retrospectively reviewed the location of the superficial peroneal nerve in a consecutive series of 35 limbs in 31 patients with entrapment of the superficial peroneal nerve. The results showed that the location of the superficial peroneal nerve was not different from the reported normal variation. However, the location of the superficial peroneal nerve in the anterior compartment in 47% of the patients in this series suggests that surgeons must explore the anterior and the lateral compartments in each patient with entrapment or neuroma of the superficial peroneal nerve.

LEVEL OF EVIDENCE

Therapeutic study, Level IV (case series-no, or historical, control group). See the Guidelines for Authors for a complete description of levels of evidence.

Isolated peripheral neurilemoma attached to the tendon of the flexor digitorum longus muscle

Neurilemomas are benign tumours arising from peripheral nerves with a Schwann cell sheath. They are normally painless and slowly growing, rarely causing motor disturbances. Neurilemomas are most common in the cranial nerves, in the trunk, the upper and lower extremities, but may appear anywhere. Especially rare are neurilemomas of the lateral peroneal nerve in the region of the fibular head and in the foot. We present the first detailed report of a neurilemoma localized between the Achilles tendon and the flexor digitorum longus muscle with separation of the tumour from the tibial nerve.

Distal sensory nerve conduction of the superficial peroneal nerve: new method and its clinical application

The superficial peroneal nerve subserves sensation on the entire surface of the dorsum of the foot, except in small areas. All previously reported techniques for evaluating nerve conduction along this nerve tested a proximal portion of the nerve. We report a new method for evaluating sensory nerve conduction of the four branches of the distal superficial peroneal nerve. Two branches to the second and third toes of the medial dorsal cutaneous nerve and two branches to the fourth and fifth toes of the intermediate dorsal cutaneous nerve were studied orthodromically and antidromically in 37 feet of 21 normal volunteers using surface stimulating and recording electrodes and with a distance of 10 cm between the stimulating and recording electrodes. Maximum nerve conduction velocities (NCV) ranged from 41.8 to 46.9 m/s, and mean response amplitude ranged from 6.5 to 7.6 microV with the orthodromic technique. Values for NCV were almost identical when elicited by antidromic and orthodromic techniques, but response amplitudes were higher with the antidromic technique. Mean amplitudes of the distal superficial peroneal nerve were about 50% of the proximal superficial peroneal, and the conduction velocity in the distal superficial peroneal was slower than that in the proximal superficial peroneal nerve, by 8-14 m/s. In seven cases, distal superficial peroneal neuropathy was confirmed with this technique: two with proper digital neuropathy, two with medial dorsal cutaneous neuropathy, and three with intermediate dorsal cutaneous neuropathy.

A posterior tibial nerve neurilemoma unrecognized for 10 years: case report

OBJECTIVE AND IMPORTANCE

Neoplasms of peripheral nerves can be obscured, especially during the early phase. The author reports a patient with a posterior tibial nerve neurilemoma (schwannoma). For a decade, the tumor was misdiagnosed as nonspecific S1 radiculopathy and psychogenic chronic pain syndrome. The patient's presentation and initial management are unique.

CLINICAL PRESENTATION

A 40-year-old woman reported severe left foot and calf pain, numbness, and weakness. The symptoms were evident during three pregnancies, and they gradually progressed. The neuropathic pain was protracted, despite implantation of a dorsal column stimulator and administration of a wide variety of medications and therapies. The symptoms were unresponsive to both inpatient and outpatient treatments, which resulted in a misdiagnosis of psychogenic pain for more than a decade. Diagnostic scans obtained by computed tomography, ultrasonography, and nuclear scintigraphy confirmed a popliteal fossa mass.

INTERVENTION

A high, large posterior tibial nerve neurilemoma was found intraoperatively, positioned just below the sciatic nerve bifurcation with extensive degenerative features and hemorrhages. Surgical resection provided immediate recovery.

CONCLUSION

Peripheral nerve tumors are rarely acknowledged clinical entities. Chronic unexplained foot and calf pain and a positive Tinel's sign should raise suspicion of posterior tibial nerve neurilemoma. Even in patients who have had such tumors for a decade, surgical resection remains the treatment of choice.