Brain Pathology Case of the Month - January 2020

FINAL DIAGNOSIS

Mixed Tumor with Schwannoma and Meningioma Components.

DISCUSSION

Neurofibromatosis type 2 (NF2) is one of the most common phakomatosis, characterized by an autosomal dominant mutation in the gene 22q12.2. NF2 patients usually present bi- or uni-lateral vestibular schwannomas. Furthermore, they tend to present other tumors, such as meningiomas and gliomas. According to the 1991 NIH consensus criteria, the diagnosis of NF2 requires either the presence of bilateral vestibular schwannomas or a positive family history and an unilateral vestibular schwannoma, in combination with either a menigioma, glioma, neurofibroma, schwannoma, or posterior subcapsular opacities (1). Our patient presented with bilateral schwannoma, with no family history of NF2.

There are very few cases in the English literature of the histopathological diagnoses of both meningioma and schwannoma in the same specimen. We found nine cases reporting the occurrences of both histologies in the same patient (4).

Some pathogenetic mechanisms have been proposed to explain concurrent tumors: the first tumor alters the tumoral microenvironment, facilitating the development of the second tumor; the multidirectional growth of the same progenitor cells; the same carcinogen stimulates both tumors; metaplasia in the original tumor; collision of two separate tumors; and residual embryonic structures developing into two separate tumors. Nevertheless, meningiomas and schwannomas have different cellular origins, and the phakomatosis carcinogenic stimuli are the same in this case (4, 2).

The standard care for intracranial neoplasms in patients with NF2 is observation until radiological confirmation of tumor growth or symptom development; however, there is no standard pattern of the mixed tumor segment in these patients. Stereotatic radiosurgery is being used as a secondary option in select patients, who have already undergone many surgical procedures and/or have surgically infeasible lesion locations. Once the malignant transformation of NF2-associated tumors occurs following radiosurgical treatment, there is no literature support for treatment approaches (3).

REFERENCES

  1. Gerber PA, Antal AS, Neumann NJ, Homey B, Matuschek C, Peiper M, et al (2009) Neurofibromatosis. Eur J Med Res 14:102-105.
  2. Nehete L, Nandeesh BN, Bharath RD, Rao MB, Arimappamagan A (2017) Cerebellopontine angle schwannoma and meningioma in contiguity: surgical implications in neurofibromatosis. J Neurol Surg A Cent Eur Neurosurg (Epub ahead of print Dec/14/2017).
  3. Nguyen T, Chung LK, Sheppard JP, Bhatt NS, Chen CHJ, Lagman C, et al. (2017) Surgery versus stereotactic radiosurgery for the treatment of multiple meningiomas in neurofibromatosis type 2: illustrative case and systematic review. Neurosurg Rev (Epub ahead of print Sep/13/2017).
  4. Porcnik A, Zele T, Prestor B (2017) Concurrent intradural meningioma and schwannoma at the same lumbar level in a patient without neurofibromatosis: a case report. Br J Neurosurg 22:1-3.

Contributed by Marcos Devanir Silva da Costa, MD, MSc, Mauricio Isaac Panicio, MD, Gregório Wrublevski Pereira, MD, PhD, Patricia Alessandra Dastoli, MD, PhD, Jardel Mendonça Nicácio, MD, Andrea Maria Cappellano, MD, Nasjla Saba-Silva, MD, Maria Teresa de Seixas Alves, MD, PhD, Sergio Cavalheiro, MD, PhD

International Society of Neuropathology