Metastatic lesions to the paranasal sinuses and skull base, while rare, carry a poor prognosis. Renal cell carcinoma has been reported in multiple case reports to be one of the most common distant malignancies to spread to the paranasal sinuses; however, it is often unrecognized by physicians, and thus treatment is delayed. To increase awareness of this disease process, we describe three cases of metastatic renal cell carcinoma to the sinonasal cavity, which is the largest case series in the literature to date.

UNASSIGNED: This study provides a comprehensive overview of the management of postoperative vasospasm after skull base surgeries. This phenomenon is rare but can be of serious sequelae.
UNASSIGNED: Medline, Embase, and PubMed Central were searched, along with examining the references of the included studies. Only case reports and series that reported vasospasm following a skull base pathology were incorporated. Cases with pathologies other than skull base, subarachnoid hemorrhage, aneurysm, and reversible cerebral vasoconstriction syndrome were excluded from the study. Quantitative data were presented as mean (Standard Deviation) or median (range), accordingly, while qualitative data were presented as frequency (percentage). Chi- square test and one-way analysis of variance were used to assess for any association between the different factors and patient outcomes.
UNASSIGNED: We had a total of 42 cases extracted from the literature. The mean age was 40.1 (±16.1) with approximately equal males and females (19 [45.2%] and 23 [54.8%], respectively). The time to develop vasospasm after the surgery was 7 days (±3.7). Most of the cases were diagnosed by either angiogram or magnetic resonance angiography. Seventeen of the 42 patients had pituitary adenoma as the pathology. Anterior circulation was nearly affected in all patients. For management, most patients received pharmacological with supportive management. Twenty-three patients had an incomplete recovery as a result of vasospasm.
UNASSIGNED: Vasospasm following skull base operations can affect males and females, and most patients in this review were middle-aged adults. The outcome of patients varies; however, most patients did not achieve a full recovery. There was no correlation between any factors and the outcome.

Mature cystic teratoma (MCT) is a benign germ cell tumor, histologically comprising components derived from mesoderm, ectoderm, and endoderm layer tissue. MCT usually has foci of intestinal components and colonic epithelia. Pituitary teratomas containing complete colon features are very rare. Here, we present three cases of sellar teratoma in two men aged 50 and 65 years and a woman aged 30 years. All patients presented with asthenia, adynamia, and loss of strength. A pituitary mass was incidentally observed on magnetic resonance imaging. Histological features showed a mature teratoma formed by gut and colonic epithelium, extended lymphoid tissue with the formation of Peyer\'s patches, and muscular layer vestiges with a fibrous capsule. The immunohistochemical panel showed reactivity to cytokeratin (CK)7, CKAE6/AE7, carcinoembryonic antigen, octamer-binding transcription factor 4, cluster of differentiation (CD)20, CD3, vimentin, muscle actin, and pituitary tumor-transforming gene 1 in isolated cells. However, alpha-fetoprotein, beta-human chorionic gonadotropin, human placental lactogen, CK20, tumor suppressor protein 53, and Kirsten rat sarcoma were negative. This article describes the clinical and histological features of rare sellar masses as well as survival after therapy.

Follicular thyroid carcinoma is a well-differentiated thyroid neoplasm that is classified into widely invasive or minimally invasive carcinoma. Vascular invasion is often characteristic of follicular thyroid carcinoma. There is an estimated 6-20% incidence of distance metastasis with the bone being the most common followed by the lungs and then the lymph nodes. Metastatic spread to the skull base is rare. This case report will cover a patient who presented with follicular thyroid carcinoma and cranial neuropathy and was found to have metastasis to the skull base.

Histiocytosis is a group of idiopathic diseases accompanied by metabolic disorders and accumulation of metabolic products in histiocytes. Isolated Rosai-Dorfman histiocytosis of central nervous system is observed in less than 5% of cases. The authors report treatment and follow-up of a patient with intracranial Rosai-Dorfman disease. There were symptoms of lesion of the left cerebellopontine angle and epileptic seizures. Preoperative MRI identified two tumors (posterior cranial fossa on the left and right-sided parasagittal neoplasm). The authors carried out total resection of supratentorial tumor, after 3 weeks - subtotal resection of tumor in posterior cranial fossa. No recurrence after total resection was observed. Irradiation of infratentorial tumor with a total focal dose of 50 Gy after 6 months resulted tumor shrinkage throughout 12 months. Radiotherapy with the same dose was repeated throughout subsequent 12-month follow-up period due to progression of this focus. This treatment had a positive effect, but new skull base foci occurred. The authors emphasize the effectiveness of total resection and lower efficiency of subtotal excision combined with radiotherapy.
Гистиоцитоз — это группа идиопатических заболеваний, при которых происходит нарушение метаболизма и накопление продуктов нарушения обмена веществ в гистиоцитах. Изолированный гистиоцитоз Розаи—Дорфмана центральной нервной системы наблюдается менее чем в 5% случаев заболевания. Авторами представлено описание случая лечения и наблюдения за пациентом с изолированной интракраниальной формой гистиоцитоза Розаи—Дорфмана. Клиническая картина заболевания представлена симптомами поражения структур левого мостомозжечкового угла и симптоматической эпилепсией. При нейровизуализационном обследовании выявлены два очага: в задней черепной ямке слева и парасагиттально справа. Выполнено тотальное удаление супратенториальной опухоли и через 3 нед субтотальная резекция новообразования в задней черепной ямке. Тотально удаленный очаг не рецидивировал. Проведенная через 6 мес фракционированная лучевая терапия в СОД 50 Гр на нерадикально удаленный очаг через 12 мес привела к уменьшению его размеров. За период наблюдения через 22 мес после облучения в связи с прогрессией данного очага повторена лучевая терапия в СОД 50 Гр — также с положительным эффектом, но отмечено формирование новых очагов в различных отделах основания черепа. В статье обращено особое внимание на эффективность радикального хирургического вмешательства и меньшую эффективность нерадикальной операции в сочетании с лучевой терапией.

Chondrosarcomas (CSs) are rare malignant tumors composed of cells derived from the transformed chondrocytes. Only 2% of the total cases of CS are found at the skull base, thus representing a 0.1-0.2% prevalence. We present the case of a patient with CS at the middle cranial fossa who was admitted for surgery to the Burdenko National Medical Research Center of Neurosurgery. In addition, we engage in a review of the literature to discuss the current approaches to the diagnostics and surgery of CS and delve deep into its embryo- and oncogenesis.

UNASSIGNED: Deep location and neurovascular structures make access to lesions of the petrous apex a significant challenge. A novel approach for these tumors is the contralateral transmaxillary approach.
UNASSIGNED: A 31-year-old male was evaluated for left abducens nerve palsy. Magnetic resonance imaging (MRI) and computed tomography revealed an enhancing, lytic lesion of the petrous apex with extension to the cavernous sinus and petroclival junction. The patient underwent a combined endoscopic contralateral transmaxillary and endoscopic endonasal transclival approach for resection of the lesion. No new or worsening neurologic deficits were noted following the procedure. Pathology revealed low-grade chondrosarcoma (grade I). Postoperative MRI revealed gross total resection of the lesion. Patient underwent adjuvant radiation therapy at the discretion of radiation oncology.
UNASSIGNED: The contralateral transmaxillary approach to the petrous apex allows for resection of lesions of the petrous apex with the ability to extend the dissection laterally. Excellent results achieved by institutions with advanced extended endoscopic endonasal experience can be reproduced in institutions with less experience. Further characterization of the risks and benefits of this approach is needed.

Introduction  Surgical treatment of petrous apex chondrosarcoma is challenging due to the location of the tumor. Using an endoscopic technique for tumor resection is favored since it provides a minimally invasive approach. Case Presentation  A 57 years old female was admitted for acute onset of left abducens nerve palsy and occasional headache mainly on the left side of the retro-orbital area with some radiation to the left occiput. Magnetic resonance imaging (MRI) and computed tomography (CT), at the time of admission, were showed lytic lesion on the left petrous apex and left part of the clivus. Results of metastatic workup were negative. The surgical procedure considered was expanded endoscopic endonasal transclival approach to the left of the petrous apex and reconstruction with a pedicled nasoseptal flap with image guidance system. The pathology confirmed chondrosarcoma on myxoid background. The surgical procedure was uncomplicated. The abducens nerve palsy was resolved in few weeks and no new deficits occurred. Postoperative MRI showed complete resection of the tumor. Conclusion  Expanded endoscopic endonasal transclival approach to petrous apex and reconstruction appears to be safe and feasible technique, capable of achieving total removal of identified lesions near the petrous apex. Nonetheless, future studies with a greater number of patients are crucial to confirm and consolidate this initial impression.

Craniofacial resection (CFR) is still considered as the gold standard for managing sinonasal malignancies of the anterior skull base (ASB), while endoscopic approaches are gaining credibility. The goal of this study was to evaluate outcomes of patients who underwent CFR at our institution and to compare our results to international literature.
Retrospective analysis of all patients undergoing CFR between 1995 and 2017, and systematic literature review according to the PRISMA statement.
Forty-one patients with sinonasal malignancy (81% with stage T4) of the ASB were included. There was no operative mortality. Complications were observed in 9 cases. We obtained 100% follow-up with mean observation of 100 months. Disease-specific survival rates were 90%, 74%, and 62% and recurrence-free survival was 85% at two, 72% at five, and 10 years follow-up, respectively. CFR as primary treatment, en bloc resection, and resection with negative margins correlated to better survival. Recursive partition analysis identified the latter as the most important prognostic factor, regardless of surgical technique. The relative risk of non-radicality was significantly higher after piecemeal resection compared to en bloc resection. Compared to 15 original articles, totaling 2603 patients, eligible for review, the present study has the longest follow-up time, the second highest 5-year OS, and the third highest 5-year DSS, despite having a higher proportion of patients with high-stage disease.
CFR in true en bloc fashion can still be considered as the treatment of choice in cases of advanced-stage sinonasal malignancies invading the ASB.

Calcifying pseudoneoplasm of the neuraxis (CAPNON) is a very rare tumor with fewer than 70 cases reported in the literature. In general, this tumor occurs intracranially either within the brain parenchyma or in an extra-axial location, but it has also been described within the spine as an extra-axial lesion.
We describe an unusual case of intracranial-extradural CAPNON involving the mastoid region. This may be only the second such case reported in the literature, as one patient with CAPNON has been reported involving the sinonasal region. Our patient was managed with surgical resection through a translabyrinthine approach with good early result.
We describe an unusual case of extradural CAPNON involving the mastoid bone. It appears that when located extradurally, this tumor may have a predilection for the bony sinuses. This little-known, generally benign entity can mimic more common lesions such as meningiomas, and should be considered in the differential diagnosis of skull base tumors, particularly when associated with heavy calcification.