Alveolar rhabdomyosarcoma is a common malignant soft tissue tumor in child and adolescents. Intracranial alveolar rhabdomyosarcoma in adults is rare, especially in the pineal region. We present a case of primary alveolar rhabdomyosarcoma of the pineal gland in a 36-year-old Chinese male with a chief complaint of dizziness, headache and a loss of balance when walking. Imaging identified a space-occupying mass in the pineal region with obstructive hydrocephalus. An endoscopic-assisted pineal mass resection was performed. Pathology revealed a solid, sheet-like growth of medium-sized, round or oval cells with map-like necrosis and some rhabdomyoblasts. The tumor cells were diffusely positive for desmin, myogenin, MyoD1, ALK, and OLIG2. Fluorescence in situ hybridization (FISH) detected FOXO1 gene rearrangement. This rare case is presented to expand the knowledge of pineal gland tumors and alert us to pay attention to the differential diagnosis of OLIG2-positive round-cell tumors of the central nervous system.

Noonan syndrome (NS), an autosomal dominant disorder, is characterized by short stature, congenital heart defects, developmental delay, and facial dysmorphism. PTPN11 mutations are the most common cause of NS. PTPN11 encodes a non-receptor protein tyrosine phosphatase, SHP2. Hematopoietic malignancies and solid tumors are associated with NS. Among solid tumors, brain tumors have been described in children and young adults but remain rather rare. We report a 16-year-old boy with PTPN11-related NS who, at the age of 12, was incidentally found to have a left temporal lobe brain tumor and a cystic lesion in the right thalamus. He developed epilepsy 2 years later. The temporal tumor was surgically resected because of increasing crises and worsening radiological signs. Microscopy showed nodules with specific glioneuronal elements or glial nodules, leading to the diagnosis of dysembryoplastic neuroepithelial tumor (DNT). Immunohistochemistry revealed positive nuclear staining with Olig2 and pERK in small cells. SHP2 plays a key role in RAS/MAPK pathway signaling which controls several developmental cell processes and oncogenesis. An amino-acid substitution in the N-terminal SHP2 domain disrupts the self-locking conformation and leads to ERK activation. Glioneuronal tumors including DNTs and pilocytic astrocytomas have been described in NS. This report provides further support for the relation of DNTs with RASopathies and for the implication of RAS/MAPK pathways in sporadic low-grade glial tumors including DNTs. © 2017 Wiley Periodicals, Inc.

Rosette-forming glioneuronal tumor (RGNT) is a recently recognized and rarely encountered tumor occurring in the fourth ventricle. RGNT was first described as a new entity for the distinct clinicopathologic features by Komori et.al. in 2002. Histologically, it is composed of 2 distinct features: a glial component, resembling pilocytic astrocytoma, and a neurocytic component forming neurocytic rosettes and/or perivascular rosettes. We report 2 extremely rare cases of RGNT arising from the spinal cord, which were misdiagnosed as ependymoma and astrocytoma preoperatively. Symptoms included dissociated sensory disturbances and episodic pain and fatigue of 2 years\' duration in case 1, as well as motor disturbance for 2 months\' duration in case 2. Magnetic resonance imaging (MRI) revealed these masses in the thoracolumbar (T7-L1) and cervicothoracic (C3-C7) spinal cord. The solid component appeared hypointense in T1-weighted MRI sequences, hyperintense in the T2-weighted MRI sequences, and heterogeneous in MRI images enhanced with gadolinium contrast medium in both cases. Gross total resection was performed via a median laminectomy. Postoperative pathological examination confirmed the diagnosis of RGNT. In addition, extensive analysis of genetic mutations was performed to explore the relationship with glioma, including telomerase reverse transcriptase promoter, isocitrate dehydrogenase 1/2, BRAF-V600E, and O(6)-methylguanine-DNA methyltransferase promoter. No radiotherapy or chemotherapy were performed in these two cases. As of the latest follow-up, both patients had a good prognosis. Given the widely varying clinical characteristics of, prognosis of, and treatments for spinal tumors, differential diagnosis is of great importance before surgery. Consideration of the tumor location and the patient\'s age and sex, in combination with the imaging features, may be the best approach to narrowing the differential diagnosis. Surgery is the preferred treatment for RGNT. We do not recommend to implement adjuvant radiotherapy and chemotherapy in these patients except the invasive or recurrent tumors. Further examination and routine follow-up should be recommended to estimate the long-term prognosis.

OBJECTIVE: To investigate the clinicopathologic features of glioneuronal tumor with neuropil-like island (GTNI).
METHODS: Four cases of intracranial and spinal GTNI, including three cases of WHO grade Ⅲ, and one case of WHO grade Ⅱ with grade Ⅲ recurrence. HE and immunohistochemical (IHC) staining were used for pathologic analysis. Fluorescence in situ hybridization (FISH) was used to detect tumor genetic changes. Related literatures were reviewed.
RESULTS: Microscopically, neuropil-like islands of varying sizes were seen within a background of glial proliferation, which showed features of astrocytoma or oligoastrocytoma. Neuropil-like islands were focal or circumscribed oval islands of varying sizes. Focally ganglion-like cells were seen. IHC staining revealed that in neuropil-like island area, the neuronal nuclei (Neu-N) as well as the cells around the neuropil-like island expressed oligodendrocyte lineage transcription factor-2 (Olig-2), and synaptophysin. The background glioma cells expressed S-100, glial fibrillary acidic protein (GFAP), vimentin and Olig-2, and the number of p53 positive cells was 10%-50%.In the neuropil-like island area, the Ki-67 labeling index was less than 3%, while in the astrocytoma area it was around 10%-25%.By FISH testing, four cases were no deletion of 1p/19q and PTEN, also no amplification of epidermal growth factor receptor.
CONCLUSIONS: GTNI is more common in adults. 1p/19q deletions are uncommon in GTNI, only seen in a few cases with background oligodendroglioma. The prognosis is related to WHO grading. GTNI often recurs locally, and the prognosis is not good, especially in the spinal cord GTNI. The recommended treatment includes tumor resection combined with radiotherapy and chemotherapy.