Following the north star: radial marker lines help preserve anatomic landmarks after local injection of anesthetic.

Injection of local anesthetic can result in distortion of local anatomic architecture. "Following the North Star" is a technique that uses radial markings to aid in better preservation of surgical landmarks.

Craniopharyngioma and other cystic epithelial lesions of the sellar region: a review of clinical, imaging, and histopathological relationships.

OBJECT: Cystic epithelial masses of the sellar and parasellar region may be difficult to differentiate on a clinical, imaging, or even histopathological basis. The authors review the developmental relationships and differentiating features of various epithelial lesions of the sellar region. METHODS: The authors performed a review of the literature to identify previous studies describing the etiological relationships and differentiating features of various cystic sellar lesions, including craniopharyngioma (CP), Rathke cleft cyst, xanthogranuloma, and dermoid and epidermoid cysts. RESULTS: There is significant evidence in the literature to support a common ectodermal origin of selected sellar and suprasellar cystic lesions, which may account for the overlap of features and transitional states observed in some cases. Research obtained from animal studies and reports of transitional cystic epithelial masses or lesions crossing over from typical to more aggressive pathological subtypes have collectively provided a solid foundation for this theory. Histological features that signify transitional entities beyond simple benign Rathke cleft cysts include squamous metaplasia, stratified squamous epithelium, and ciliated or mucinous goblet cells in squamous-papillary CPs. Several studies have identified key clinical, imaging, and histopathological features that can be used in the differentiation of these lesions. CONCLUSIONS: The pattern of embryological formation of the hypothalamic-pituitary axis plays a major role in its propensity for developing cystic epithelial lesions. Subsequent inflammatory, metaplastic, and neoplastic processes may promote further progression along the pathological continuum, ranging from benign epithelial cysts to aggressive neoplastic cystic CPs. Selected clinical, imaging, and histopathological features can be used collectively to help differentiate these lesions and assign a formal diagnosis, thus accurately guiding further treatment.

[Amelanotic malignant melanoma of the scalp clinically resembling a proliferating trichilemmal cyst]. / Amelanotisches Melanom der Kopfhaut klinisch imponierend als proliferierende Trichilemmalzyste.

HISTORY AND FINDINGS: A 37-year-old woman was admitted with an ulcerated tumor of the scalp together with an enlarged cervical lymph node. The clinical features resembled proliferative trichilemmal cyst. INVESTIGATIONS: Fine needle aspiration of the lymph node revealed an amelanotic metastasis of a malignant melanoma. TREATMENT AND COURSE: The entire tumor was removed and a radical neck-dissection performed. Histopathological examination confirmed the diagnosis of metastatic malignant melanoma. CONCLUSION: Proliferative trichilemmal cysts and malignant melanoma of the scalp are rare, but should be considered as differential diagnoses of neoplasm in this part of the body.

[Epidermoid cyst of the third ventricle. Report of a case]. / Kyste épidermoïde du troisième ventricule. Une observation.

We report a case of epidermal (or epidermoid) cyst, in a 36-year-old man which developed in the third ventricle. Clinical manifestations were headaches and memory disturbances. On CT scan the tumor occupied the entire third ventricle but was mainly developed on the left side. On CT reconstructed images, the floor of the third ventricle was clearly visible. Using a trans-ventricular approach, the tumor, closely related to the left part of hypothalamus, was totally removed. Later on, because of persistent hydrocephalus, a ventricular shunt was inserted. An aseptic meningitis occurred and resolved spontaneously. The patient exhibited a postoperative transitory Korsakoff's syndrome. Postoperative endocrine investigations showed hypopituitarism. Some intra-ventricular epidermal cysts have been reported, especially involving the fourth ventricle. Their development into the third ventricle is unusual, and in early reports their precise origin appears doubtful. Although they have no characteristic radiological features, the location of epidermal cysts is clearly defined by the CT scan and especially MRI. It would be possible to totally remove epidermal cysts of the third ventricle, avoiding the risk of recurrence.

Quiste eruptivo de pelo vellus: tratamiento con radiocirugía / Eruptive vellus hair cysts: treatment with radiosurgery

Se describe el caso de una niña de 10 años que presenta quistes eruptivos de pelo vellus. Presentaba múltiples pápulas marrón oscuro en la parte anterior del tórax. Se confirma el diagnóstico a través del estudio histológico que muestra estructuras císticas delimitadas por varias capas de epitelio escamoso, ubicadas en la dermis media, conteniendo material queratinoso y pelos vellus en su interior. Se propone su remoción con radiocirugía, que es un método simple, rápido, barato y sin complicaciones

[A case of epileptic laughter associated with temporal epidermoid cyst: surgical treatment combined with subdural grid electrode study].

A case of epileptic laughter associated with deep right temporal epidermoid cyst is reported. Interictal EEG with subdural grid electrodes demonstrated multifocal spike discharges in the right temporal lobe. Ictal EEG localized the epileptogenic foci at the base of the anterior medial temporal lobe. After standard temporal lobectomy, the tumor was completely removed. The patient is free from seizures postoperatively.

Brainstem auditory evoked potentials and blink reflexes in patients with pontocerebellar angle tumors.

Brainstem auditory evoked potentials (BAEP) and blink reflexes (BR) were obtained from 13 patients with pontocerebellar angle (PCA) tumors whose pathological diagnosis was as follows: 7 acoustic neurinoma, 3 meningioma, 1 neurinoma, 1 brain stem epidermoid tumor, 1 arteriovenous malformation. The most prominent abnormality was noted in BAEP generated by stimulating the ear ipsilateral to the lesion and ipsilateral R1 reflexes obtained from ipsilateral stimulation of the supraorbital nerve.

Intrathalamic epidermoid tumor. Case report.

A case of an intrathalamic epidermoid tumor is reported, and the literature is reviewed with regard to the incidence, location, and etiology of intracerebral epidermoid tumors. The high frequency of mental symptoms associated with these tumors is also discussed.