Popliteal schwannoma mimicking baker cyst: an unusual case

Tibial Nerve Schwannoma: An Unexplained Cause of Lateral Foot Pain - A Rare Case Report and Review

Introduction:

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.

Case Report:

We report the case of a schwannoma arising from the tibial nerve located in the left popliteal fossa. The patient presented with the left foot pain in the lateral plantar region without any motor deficit. The pre-operative diagnosis was made with magnetic resonance imaging (MRI) scan. He was subjected for neurolysis and excision biopsy of the lesion. The surgical specimen consisted of encapsulated white-yellow mass with irregular contours, measuring 2 × 3 cm. The cut section revealed cystic degenerations with areas of hemorrhage and necrosis. The patient reported symptom free in the post-operative period and during follow-up. Marginal excision appears to be recommended therapy for this tumorous lesion, without any evidence of recurrence during follow-up.

Conclusion:

A benign nerve sheath tumor of a peripheral nerve could be a possibility for long-standing neuropathic pain in the foot, ankle, and leg, wherein all other possibilities have been ruled out. The meticulous examination of the entire length of the tibial nerve including sciatic nerve by palpation and percussion was helpful in diagnosis which should be confirmed by MRI scan. The excision biopsy remains the gold standard treatment of choice for schwannoma of the peripheral nerve.

The role of ultrasound-guided fine needle aspiration biopsy in musculoskeletal diseases

Ultrasonography (US) is a readily available non-invasive tool useful for the detection of musculoskeletal and soft tissue masses. Although X-Ray is often the first imaging study for evaluating both bone and soft tissue lesions, and magnetic resonance imaging and computed tomography are mandatory in lesions staging, US is increasingly used for the early assessment of musculoskeletal and soft-tissue masses and for guiding procedures and biopsies. Surgical biopsy or fine needle aspiration biopsy (FNAB) is needed to ascertain the nature of any lesion. FNAB is a low cost technique, safer and less traumatic than an open surgical biopsy. Significant complications are rare, mostly related to the site of biopsy. Knowledge of indications, limitations, anatomical and pathological access, adequate technical expertise in US imaging and in intervention skills are the critical factors of the appropriate and safe use of FNAB. By now, the role of FNAB in musculoskeletal diseases is controversial and there is still a heated debate in the scientific community.

Arthroscopic patterns of the poster-medial aspect of the knee joint: classification of the gastrocnemius-semimembranosus gateway and its relationship with Baker's cyst

BACKGROUND

The gastrocnemius-semimembranosus bursa may communicate with the knee joint. The arthroscopic anatomy of the posteromedial aspect varies depending on the angle of the oblique popliteal ligament, the level at which it crosses the medial gastrocnemius tendon, and its relationship with the capsular joint and synovia. The aim of this paper is to identify possible patterns, and to evaluate their characteristics and their relationship with Baker's cyst.

METHODS

data archived from 185 consecutive arthroscopies were evaluated; an anatomic description and classification was carried out; the percentages of association with BC and the associated pathologies were reported.

RESULTS

The different anatomies were classified into six groups based on the relationship above the medial gastrocnemius tendon, the capsular joint and synovia. The prevalence of Baker's cyst was 28.3%. The main associated intra-articular pathological condition was the contemporary presence of a meniscal tear and chondropathy.

CONCLUSION

Exploration of the posterior aspect of the knee must be performed routinely. Knowing the possible anatomy patterns of the posteromedial arthroscopic aspect of the knee joint could help to identify the cyst and its gateway, thus facilitating its treatment.

LEVEL OF THE EVIDENCE

III.