Intramasseteric Schwanoma mimicking an isolated cheek mass: Case report and review of literature

Nivolumab induced pulmonary sarcoid-like granulomas with a concurrent pleural schwannoma: A pathologic-radiologic correlation of a rare condition mimicking metastatic melanoma

Nivolumab is an anti-PD-1 antibody. The mechanism of action of nivolumab is inhibition of binding between PD-1 and PD-1 ligand. This causes activation of antigen-specific T cells that were previously unresponsive to cancer cells. This unique mechanism of action attributes the widespread use of nivolumab for the treatment of a variety of neoplastic conditions. On the other hand, this mode of action is associated with adverse effects as well. Schwannoma, also called neurilemmoma, is a benign peripheral nerve sheath tumor. Pleural schwannomas are very rare and very few cases have been reported in the medical English literature so far. Herein, we report a very rare case of concurrent presence of Nivolumab induced pulmonary sarcoid-like granulomas along with primary benign pleural schwannoma in a 49-year-old male. He was diagnosed with malignant melanoma of the right upper arm for which he underwent surgery and was receiving adjuvant chemotherapy. He developed pneumonitis during chemotherapy, and on imaging multiple reticular and nodular interstitial infiltrates were seen along with an incidental pleural mass with a high suspicion for metastasis. Wedge biopsy of the interstitial infiltrates was done and they were found to be pulmonary granulomas related to the nivolumab therapy he was receiving. The patient underwent excision of the pleural mass which showed histopathological and immunohistochemical features of schwannoma. The two conditions are unrelated and rarely encountered simultaneously. The radiologic and pathologic correlation along with differential diagnosis of these conditions are discussed.

Nodular fasciitis growing at the port site of robotic surgery for rectal cancer

Background

Nodular fasciitis (NF) is a type of rare and rapidly growing tumor that affects the muscular fascial layers. Due to its locally aggressive nature and rapid growth, NF can be mistaken as a malignant process on either clinical or histological grounds.

Case presentation

A 61-year-old man was affected by rectal cancer. We performed a robotic, high-anterior resection with lymph node dissection. According to the 8th edition of Union for International Cancer Control, the diagnosis was stage I pT2N0M0. During a routine follow-up 1.5 years after the robotic surgery, a computed tomography examination revealed a tumor in the upper right abdominal wall, at the site of the surgical port, that measured 45 mm. Magnetic resonance imaging indicated a hypo-intensive mass within the right straight muscle of the abdomen. Port site recurrence following the robotic surgery for rectal cancer was suspected, and an ultrasound-guided fine-needle aspiration was performed; it revealed a low-grade myofibroblastic tumor or benign neoplasm, but was inconclusive. We performed an excision of the lesion, and histopathology confirmed NF, seen as a solid, nodular, spindle-cell lesion. The patient was postoperatively followed for more than 1 year without any sign of recurrence of either cancer or NF.

Conclusions

NF is histologically benign, but local recurrence frequently occurs. We encountered a patient with NF at the port site after robotic surgery for rectal cancer.

Pleural Schwannoma Suspected as Metastasis of Breast Cancer

Patient: Female, 62-year-old

Final Diagnosis: Pleural schwannoma

Symptoms: Lt. breast mass

Medication: —

Clinical Procedure: —

Specialty: Surgery

Intramasseteric Schwannoma Derived from the Masseteric Nerve

This report documents the intramasseteric onset of a schwannoma of the masseteric nerve, which is extremely rare. The patient was a 24-year-old woman who noticed an asymptomatic mass in the parotidomasseteric region 1 year before; a soft painless mass located near the angle of the left mandible was observed during the initial examination. No neuropathy, including sensory deficit, facial nerve paralysis, or trismus, was observed. Contrast-enhanced magnetic resonance imaging revealed an isolated neoplastic lesion within the body of the masseter muscle; the lesion exhibited low-signal intensity on coronal T1-weighted imaging and high-signal intensity on T2-weighted imaging with somewhat heterogeneous early uptake of contrast medium. The tumor was resected under general anesthesia and was found to be solid with distinct margins, enclosed within the masseter muscle, and continuous with a branch of the masseter nerve identified using intraoperative electrical stimulation. The lesion was a pale yellow solid mass encapsulated in a smooth membrane measuring 3.2 × 1.7 × 1.6 cm. Histopathological examination revealed a mixture comprising Antoni A pattern with Verocay bodies surrounded by oval nuclei exhibiting nuclear palisading, and an Antoni B pattern with loss of the characteristic cellular arrangement and separation of the cells, creating a more distinct individual tumor cell morphology. The final histopathological diagnosis was schwannoma. No complications, such as trismus or facial nerve paralysis, and no tumor recurrence were observed in the 1 year that has elapsed postoperatively.