Slow-Growing Pituitary Metastasis from Renal Cell Carcinoma: Literature Review.

BACKGROUND: Tumor metastasis to the pituitary is rare, most commonly reported with either breast or lung cancer metastasizing to the neurohypophysis. Pituitary metastases of renal cell carcinoma (RCC) are by contrast infrequently described even within this scarce literature. We present an illustrative case of RCC pituitary metastasis 15 years after radical nephrectomy for primary disease and a review of the published literature. CASE DESCRIPTION: A 69-year-old female was diagnosed with a large sellar mass with suprasellar extension. The initial radiologic diagnosis was most in keeping with pituitary macroadenoma, although prominent vascular flow voids were noted. Endoscopic endonasal transsphenoidal adenectomy was challenging on account of significant intraoperative hemorrhage from an unusually vascular tumor. Pathologic examination supported a diagnosis of metastatic clear cell renal carcinoma. Literature review identified 41 cases of RCC pituitary metastasis since 1984. The mean age at time of diagnosis with pituitary metastasis was 59.5 years (range 35-81 years, 73% male). Pituitary metastasis was the initial presentation of RCC in 10 patients. The median time from RCC diagnosis to pituitary metastasis was 1 year (range 0-27 years). Surgical resection was performed for 30 patients, of which 47% reported a highly vascular tumor. CONCLUSIONS: We highlight the potential for delayed metastasis to the pituitary to masquerade as a macroadenoma. Imaging consistent with rich vascularity should bring the diagnosis of RCC metastasis into the differential and is important to note when planning surgical resection in such cases.

Giant Juvenile Ectopic Schwannoma of the Temporal Bone.

BACKGROUND: Ectopic intracranial schwannomas (those that do not arise from a named cranial nerve) are rare. They account for <2% of surgically resected central nervous system schwannomas. CASE DESCRIPTION: We report the case of a 14-year-old boy presenting with a left conductive hearing loss and temporal bone deformity. No facial or cranial nerve deficits were present. Cross-sectional imaging demonstrated a large expansile extra-axial temporal bone mass, extending into and distorting the middle cranial fossa. At surgical resection the tumor was functionally and anatomically distinct from the facial nerve or any other identifiable neural structure within the middle ear or temporal bone. Histology confirmed a World Health Organization grade 1 schwannoma. CONCLUSIONS: This is the first reported case of a giant juvenile ectopic schwannoma within the temporal bone.

Therapeutic Targeting of Histone Modifications in Adult and Pediatric High-Grade Glioma.

Recent exciting work partly through The Cancer Genome Atlas has implicated epigenetic mechanisms including histone modifications in the development of both pediatric and adult high-grade glioma (HGG). Histone lysine methylation has emerged as an important player in regulating gene expression and chromatin function. Lysine (K) 27 (K27) is a critical residue in all seven histone 3 variants and the subject of posttranslational histone modifications, as it can be both methylated and acetylated. In pediatric HGG, two critical single-point mutations occur in the H3F3A gene encoding the regulatory histone variant H3.3. These mutations occur at lysine (K) 27 (K27M) and glycine (G) 34 (G34R/V), both of which are involved with key regulatory posttranscriptional modifications. Therefore, these mutations effect gene expression, cell differentiation, and telomere maintenance. In recent years, alterations in histone acetylation have provided novel opportunities to explore new pharmacological targeting, with histone deacetylase (HDAC) overexpression reported in high-grade, late-stage proliferative tumors. HDAC inhibitors have shown promising therapeutic potential in many malignancies. This review focuses on the epigenetic mechanisms propagating pediatric and adult HGGs, as well as summarizing the current advances in clinical trials using HDAC inhibitors.