Inflammatory pseudotumor of the median nerve

Abstract

The authors report the presence of an inflammatory pseudotumor of the median nerve in a young woman who presented with a sensorimotor deficit in the median nerve area. Magnetic resonance (MR) images revealed a fusiform mass in the nerve, and the patient underwent surgery for a suspected peripheral nerve-sheath tumor. Her clinical condition improved slowly and notably. Histological study revealed a heterogeneous lymphoid infiltration with mononuclear cells, lymphocytes (mostly T cells), and plasmocytoid cells. Because of the unknown significance of this infiltration, the patient was examined to exclude the possible diagnosis of a systemic tumoral process. All the studies yielded negative results and no systemic disease was found. Later, control MR imaging revealed no tumoral remains, and electromyography demonstrated progressive improvement of median nerve function. The follow-up period has been 8 years. The cause of the lesion is unknown. The differential diagnosis includes benign and malignant peripheral nerve-sheath tumors, lymphoma, and all tumorlike lesions of peripheral nerves.

Posterior Interosseus Nerve Palsy Resulting From Inflammatory Myofibroblastic Pseudotumor: Case Presentation

“…Before a histologic evaluation of the mass, these lesions can mimic other processes, such as schwannomas, neurofibromas, peripheral nerve sheath tumors, amyloid pseudotumors, primary lymphomas, tuberculoid leprous neuropathy, and hypertrophic inflammatory neuropathies [6]. Ideally, the mass can be resected while sparing the adjacent nerve as much as possible.…”

“…Ideally, the mass can be resected while sparing the adjacent nerve as much as possible. One prior publication reported regrowth of the lesion that affected the proximal and distal nerve stumps 2 years after initial resection [6]. In contrast, in a separate case with only partial resection of the most affected nerve fascicles, no tumor regrowth was found on annual contrast‐enhanced magnetic resonance imaging studies over an 8‐year follow‐up period [6].…”

“…Electrodiagnostic studies can be used to further characterize, localize, and help prognosticate the neurologic outcome [5]. No previous report has described a case of PIN injury caused by inflammatory myofibroblastic pseudotumor, a heterogeneous group of benign tumor‐like lesions that consist of a chronic inflammatory process associated with reactive proliferation of the mesenchymal tissue with collagen deposits [6,7]. We describe the first reported case, to our knowledge, of PIN palsy that resulted from inflammatory myofibroblastic pseudotumor.…”

Inflammatory Myofibroblastic Tumor on Intercostal Nerve Presenting as Paraneoplastic Pemphigus with Fatal Pulmonary Involvement

“…The common sites of this lesion are the lung (the originally described location), respiratory tract, gastrointestinal tract, orbit, liver, spleen, lymph nodes, heart, and brain (2, 3). Seven cases of intraspinal IMT have been reported (4, 5), and only five cases of IMT involving peripheral nerves have been previously described (6, 7). Although imaging techniques have made evident progress, they cannot be used for a preoperative diagnosis of IMT, and only histological examinations are capable of identifying its inflammatory character.…”

Inflammatory pseudotumor of the peroneal nerve

“…1,3,4 IPT involving the peripheral nervous system has also been recognized, and to our knowledge six cases (including the present case) have been reported in the English-language literature. 2,[5][6][7] We report a 44-year-old woman who presented with left foot drop of 18 months' duration. In the last 4 months symptoms progressed, with increasing ankle weakness and progressive foot drop and numbness along the lateral aspect of the left foreleg and dorsum of the left foot.…”