Carlson, Matthew L.

Object The authors describe the unique occurrence of nodular enhancement within the fundus of the internal auditory canal (IAC) lateral to the preoperative radiological tumor margin following gross-total vestibular schwannoma (VS) resection. Methods The nature of the study was a retrospective chart review of records. The authors reviewed the cases of all patients who underwent microsurgical resection of a VS between January 2000 and January 2010 at a single tertiary referral center. Patients with incomplete resection, neurofibromatosis Type 2, and those with fewer than 2 postoperative MR images available for review were excluded. Postsurgical patients with IAC enhancement located lateral to the preoperative imaging–delineated tumor margin were identified. Lesion morphology was characterized on serial MR imaging studies. Clinical follow-up and outcomes were recorded. Results Over the past decade, 350 patients underwent microsurgical VS resection. Of these, 16 patients met study criteria and were found to have postsurgical enhancement in the distal aspect of the IAC lateral to the imaging limits of the preoperative tumor margin on the first postoperative MR imaging study (37.5% women, median age 45 years). Initial MR imaging was performed at a mean of 3.1 months following surgery, and the mean radiological follow-up duration was 39.8 months (range 16.4–101.9 months). None of the 16 patients developed recurrence during the follow-up course. Conclusions In contrast to previous publications that have reported a high rate of recurrence in cases involving nodular enhancement within the original tumor bed, postoperative enhancement in the IAC lateral to the original tumor margin appears to carry much less risk for tumor recurrence. These findings may be helpful when counseling patients on the recommended frequency of postoperative follow-up imaging.

Kikuchi-Fujimoto disease is a rare, self-limited, histiocytic, necrotizing lymphadenitis first described in Japan in 1972. Necrosis of lymph node tissue is caused by apoptosis and may be virally induced. It commonly presents with cervical lymphadenitis and fever. Despite its low incidence, Kikuchi-Fujimoto disease should be considered in patients with persistent lymphadenopathy. Originally thought to occur only in young Asian women, it is now recognized in other geographic regions. We report a 30-year-old white woman with Kikuchi-Fujimoto disease. We discuss the clinical features, differential diagnosis, radiography, pathology, and outcome.

Neurofibromatosis Type 2 (NF2) is a rare autosomal dominant disorder characterized by the development of benign tumors of the peripheral nervous system and the CNS, including schwannomas, meningiomas, and ependymomas. The gene responsible for the development of NF2 acts as a tumor suppressor gene. Stereotactic radiotherapy (SRT) or single-fraction stereotactic radiosurgery has been increasingly used in the past decades to treat benign tumors in patients with NF2. These radiotherapy methods are less invasive and can be potentially used to treat multiple tumors in a single session. The risk of inducing malignancy is unclear. Few reports exist of malignant peripheral nerve sheath tumors, meningiomas, or ependymomas occurring after SRT or stereotactic radiosurgery in patients with NF2. The authors present the first documented case of rhabdomyosarcoma following SRT for multiple NF2-associated schwannomas. Compared with patients with sporadic tumors, NF2 patients having a germline tumor suppressor gene defect may be more prone to secondary malignancies after treatment involving radiation therapy.