Neurocytoma of the VIIIth cranial nerve: case report.

OBJECTIVE AND IMPORTANCE: Neurocytomas are uncommon tumors of the CNS. To date, none have been described in association with a cranial nerve. We described the clinicopathological features of an example arising in the cochlear-vestibular portion of the VIIIth nerve with extension into the cerebellopontine angle. CLINICAL PRESENTATION: The patient, a 42-year-old female, presented approximately 6 months ago with several episodes of worsening dizziness. On magnetic resonance imaging studies, a 2-cm enhancing lesion occupying the left internal auditory canal and protruding into the cerebellopontine angle cistern was detected with signal characteristics suggestive of vestibular neuroma. INTERVENTION: At surgery, the tumor was seen to originate from the cochlear-vestibular nerve bundle lying within the internal auditory canal, extended laterally to the level of the fundus and 4 mm medially into the cerebellopontine angle. No dural attachment was noted. With use of sharp dissection and bipolar cautery, portions of the tumor within the auditory canal were debulked. CONCLUSION: A unique example of a neurocytoma in association with a cranial nerve is documented. Possible explanations for the occurrence are explored. The topography of neurocytomas continues to expand.

Recurrent solitary fibrous tumour in the cerebellopontine angle.

Solitary fibrous tumours (SFT) of the central nervous system are rare. They resemble meningioma in clinical presentation, imaging features and appearance at surgery. Schwannoma, hemangiopericytoma and other spindle cell mesenchymal neoplasms should also be considered in the differential diagnosis. Although the histogenesis of this tumour is still debated, strong CD34 reactivity of the tumour cells suggests that SFT is mesenchymal. We present the clinical, radiological, and pathological features of an SFT located in the cerebellopontine angle (CPA). A 55-year-old female presented with 6 months of headache. The MRI scan showed a contrast enhancing ovoid mass in the left CPA. At craniotomy, the tumour was completely resected. Histolopathological diagnosis was of meningioma. Three years later, the symptoms recurred and an MRI scan demonstrated tumour recurrence. A repeat craniotomy was performed and the lesion was again completely excised. Tumour morphology on histopathology and immunoreactivity for CD34 of the tumour cells supported the diagnosis of SFT. Review of the original tumour also disclosed immunoreactivity for CD34. Ki67 labeling indices were less than 1% in both tumours.

Pituitary carcinoma: a clinicopathological review.

Pituitary carcinomas are rare tumors; less than 100 well-documented cases have been reported to date. Such tumors are aggressive and associated with a high mortality rate. The molecular events leading to the development of pituitary carcinomas are largely unknown. Recent studies have only begun to shed light on the probable mechanisms of tumor initiation and progression. A review of the clinicopathological and molecular genetic characteristics of pituitary carcinomas is presented.

Insights into meningioangiomatosis with and without meningioma: a clinicopathologic and genetic series of 24 cases with review of the literature.

Meningioangiomatosis (MA) is a rare seizure-associated lesion of presumed hamartomatous or developmental origin. It is occasionally combined with a neoplasm, most commonly meningioma (MA-M). In the current study, we examined 24 cases (14 pure MA, 10 MA-M) using immunohistochemistry for merlin, protein 4.1 B, progesterone receptor (PR), and MIB-1, as well as FISH for NF2 and 4.1B gene dosages. Nine cases of MA-M (90%) had gene deletions (NF2/4.7B), protein losses (merlin/protein 4.1B), and/or PR positivity, with a similar or identical phenotype in both components. No PR positivity or gene deletions were seen in pure MAs, though merlin and/or protein 4.1B were immunonegative in six cases. Our data suggest that in most MA-Ms, the MA component is neoplastic, likely representing an exuberant perivascular pattern of spread from the meningioma, rather than an underlying hamartoma. This pattern of spread may be facilitated by meningiomas that are predominantly leptomeningeal or intracerebral in origin. It remains important to distinguish this pattern from true brain invasion, given the more ominous prognostic significance of the latter. In contrast, most perivascular spindled cells of pure MA are genetically and immunohistochemically similar to non-neoplastic meningothelial cells, consistent with current histogenetic theories.

Suprasellar haemangioblastoma. Report of two cases and review of the literature.

We report 2 patients with suprasellar haemangioblastoma (HBL). The first, a 54-year-old man, presented with headache and gradually worsening bilateral visual field defects that had progressed to complete blindness on the right side. Computed tomography (CT) and magnetic resonance imaging (MRI) of the brain demonstrated a suprasellar mass. The mass was removed through a pterional craniotomy. The postoperative course was uneventful. He had no stigmata of von Hippel-Lindau (VHL) disease. After 5 years follow-up, vision in the left eye is normal but the right eye remains blind and MRI reveals no recurrence. The second, a 38-year-old man presented with a 2-month history of severe headaches and complete visual loss in the left eye. He had had surgery for excision of a cerebellar HBL, 5 years prior to this presentation. CT and MRI revealed a residual mass in the posterior fossa and a new suprasellar mass. He underwent craniotomy and subtotal excision of the suprasellar tumour. The histological diagnosis was HBL in both patients. HBL in the sellar and suprasellar region are rare and may be sporadic or occur in association with VHL disease. The literature is reviewed and diagnosis and treatment options discussed.

Mid-esophageal ulceration and candidiasis-associated distal esophagitis as two distinct clinical patterns of tetracycline or doxycycline-induced esophageal injury.

BACKGROUND: Tetracyclines may cause esophageal injury. GOALS: The aims of this study are to describe 2 distinct clinical patterns of esophageal injury induced by tetracycline or its derivate doxycycline and to compare these patterns with respect to demographic, endoscopic, and clinical characteristics of the patients. STUDY: Forty-eight patients with the diagnosis of doxycycline- or tetracycline-induced esophageal injury by endoscopy were analyzed retrospectively. The patients were considered in 2 groups according to the type and the location of esophageal lesions (Group A: mid-esophageal ulceration, n = 18; Group B: distal esophagitis, n = 30). RESULTS: Patients in Group A were significantly younger than in Group B (P = 0.0014). In Group A, 15 patients (83%) had single ulceration, 2 (11%) double, and 1 (6%) circumferential at the mid-esophagus. In Group B, all patients had multiple micro-ulcerations in the distal esophagus. Development of mid-esophageal ulceration was induced predominantly by doxycycline, whereas distal esophagitis was induced by tetracycline. The description of drug ingestion with little or no water by patients in Group A was significantly more frequent than in Group B (94% vs. 10%, P < 0.001). Associated medical and benign gastric diseases and esophageal candidiasis were significantly more frequent in Group B (P = 0.006, P < 0.001, P < 0.001, respectively). Prompt response to medical therapy was observed in both groups with no significant difference (P = 0.093). CONCLUSIONS: The type of tetracyclines used by patients may give some clues to physicians on the pattern of esophageal injury because mid-esophageal ulceration seems to be more frequently associated with doxycycline and distal esophagitis with or without candidiasis with tetracycline.

Xanthelasmas of the upper gastrointestinal tract.

BACKGROUND: Gastric xanthelasma is a benign and uncommon lesion with a variably reported frequency, while esophageal and duodenal xanthelasmas are quite rare. METHODS: Seventeen patients who had the diagnosis of xanthelasma in the upper gastrointestinal tract were analyzed retrospectively with respect to their demographic, clinical, endoscopic, and histopathologic features. All lesions suspected as xanthelasma were totally removed by either hot biopsy forceps or a snare with the technique of endoscopic mucosal resection. RESULTS: The incidence of upper gastrointestinal xanthelasmas in 7320 patients who had upper gastro-intestinal endoscopy was 0.23%. There were 9 (53%) men and 8 (47%) women, with a median age of 50 years (range, 24-80 years). The most common location of xanthelasmas was the stomach (76%), followed by the esophagus (12%) and duodenum (12%). All lesions were observed as yellow-white colored plaques at endoscopy. Multiple xanthelasmas were detected in 4 patients (24%); in the duodenum in 2, esophagus in 1, and stomach in 1. One patient had xanthelasma within a gastric hyperplastic polyp. The size of the lesion was less than 5 mm in diameter in 14 (82%) patients and between 5 and 10 mm in diameter in 3 (18%). Thirteen (76%) patients had moderate to severe atrophic gastritis, while the remainder had normal gastric mucosa. CONCLUSIONS. Xanthelasmas of the upper gastrointestinal tract were mostly located in the stomach in the present series, which includes the second and third reported cases of duodenal xanthelasma, the second case of xanthelasma developed within a hyperplastic gastric polyp, and the fourth and the fifth cases of esophageal xanthelasma.

The utility of cytokeratins 7 and 20 (CK7/20) immunohistochemistry in the distinction of short-segment Barrett esophagus from gastric intestinal metaplasia: Is it reliable?

BACKGROUND: The purpose of the present correlative immunohistochemical study was to assess the utility of cytokeratin (CK7 and CK20) expression in the diagnosis of short-segment Barrett esophagus, particularly its efficacy in differentiating Barrett mucosa from intestinal metaplasia of the gastric cardia and corpus. METHODS: Two groups of endoscopic biopsy specimens were examined, including 20 endoscopic biopsy specimens of short-segment Barrett esophagus (Group A) and equal number exhibiting Helicobacter pylori associated intestinal metaplasia of the gastric cardia and corpus (Group B). All were investigated by immunohistochemistry using the standard ABC method for CK7 and CK20 expression. Fisher's exact test was used for statistical analysis of Barrett CK7/20 and gastric CK7/20 patterns between the groups. RESULTS: The anticipated pattern of reactivity in Barrett mucosa (CK7: strong diffuse positivity in superficial and deep glands; CK20: positivity in surface epithelium and superficial glands) was seen in 2 cases of Group A specimens. The expected gastric pattern (CK7: patchy immunostaining with variable involvement of deep glands; CK20: patchy immunostaining of superficial and deep glands in incomplete intestinal metaplasia / absence of CK7 immunoreactivity with strong CK20 staining in superficial and deep glands in complete intestinal metaplasia) was seen in 8 cases of Group B specimens. The respective sensitivity and false-negativity values of CK7/20 staining for Barrett pattern in Group A were 10% and 90%, respectively. These values for gastric pattern in Group B were 40% and 60%, respectively. The specificity and false-positivity values of both patterns were same (100% and 0%, respectively). There was no statistically significant difference for Barrett pattern between the two groups (P = 0.487), while the observation of gastric pattern was significantly higher in Group B than in Group A (P = 0.02). CONCLUSIONS: We concluded that these hypothesized and recently applied diagnostic criteria involving CK7 and CK20 immunoreactivity are not reliable in distinguishing short-segment Barrett esophagus from intestinal metaplasia as seen in gastric cardia and corpus.

Gastric polypoid lesions: analysis of 150 endoscopic polypectomy specimens from 91 patients.

AIM: To analyze gastric polypoid lesions in our patient-population with respect to histopathologic features and demographic, clinical, and endoscopic characteristics of patients. METHODS: Clinical records and histopathologic reports of patients with gastric polypoid lesions were analyzed retrospectively. All lesions had been totally removed by either endoscopic polypectomy or hot biopsy forceps. The histopathologic slides were re-evaluated by the same histopathologist. RESULTS: One-hundred and fifty gastric polypoid lesions were identified in 91 patients. There were 53 (58%) women and 38 (42%) men with a median age of 53 (range, 31 to 82) years. The most frequent presenting symptom was dyspepsia that was observed in 35 (38.5%) patients. Symptoms were mostly related to various associated gastric abnormalities such as chronic gastritis or H pylori infection rather than polypoid lesion itself. Polypoid lesions were commonly located in the antrum followed by cardia. Out of 150 lesions, 80 (53%) had the largest dimensions less than or equal to 5 mm and only 7 were pedunculated. The frequencies of hyperplastic polyps, foveolar hyperplasia, and fundic gland polyps were 46%, 18%, and 14% respectively. We also detected gastritis varioliformis in 12 specimens, lymphoid follicles in 9, 4 adenomatous polyps in 4, polypoid lesions with edematous mucosa in 4, inflammatory polyps in 3, and carcinoid tumor in 1. Adenomatous changes were observed within two hyperplastic polyps and low grade dysplasia in one adenoma. Histopathologic evaluation of the surrounding gastric mucosa demonstrated chronic gastritis in 72 (79%) patients and H pylori infection in 45 (49%). CONCLUSION: Hyperplastic polyps are the most frequently encountered subtype of gastric polypoid lesions. They are usually associated with chronic gastritis or H pylori gastritis. Contrary to the previous belief, they may harbour adenomatous changes or dysplastic foci. Therefore, endoscopic polypectomy seems as a safe and fast procedure for both diagnosis and treatment of gastric polypoid lesions at the same session. In addition, edematous mucosa may appear misleadingly as a polypoid lesion in some instances and it can be ruled out only by histopathologic examination.

Congenital and childhood plexiform (multinodular) cellular schwannoma: a troublesome mimic of malignant peripheral nerve sheath tumor.

We present six cases of a plexiform nerve sheath tumor of childhood that previously had been designated a form of malignant peripheral nerve sheath tumor (MPNST), and we provide evidence that such tumors are in fact benign plexiform cellular schwannomas. At presentation, the four girls and two boys ranged in age from 2 to 15 months with tumors of the leg (four), deep groin and upper thigh (one), and pelvis (one). Of the six lesions, five were congenital and none was associated with type 1 neurofibromatosis. Tumor sizes ranged from 2.0 to 9 cm, with three larger than 5 cm. Three tumors were well circumscribed, two were purely infiltrative, and one had a mixed circumscribed and infiltrative growth pattern. Peripheral nerve involvement was evident in two cases. Grossly, the tumors were multinodular or plexiform in configuration and, on sectioning, lobulated and homogeneously tan without necrosis. Characteristic histologic features included hypercellularity, composition of cells spindle in shape with elongate hyperchromatic nuclei, and indistinct cellular outlines. Their nuclei varied minimally in size and shape but were at least three times the size of typical neurofibroma nuclei. Mitoses were seen in every tumor and in the areas of greatest proliferative activity ranged from 4 to 31/10 high power fields. MIB-1 staining of at least 30% of the cells was noted in three cases. In five cases in which p53 immunoreactions were performed, no nuclear staining was evident. That the tumors are schwannomas was evident from their uniform strong staining for S-100 protein and an ultrastructure in all five cases showing only differentiated neoplastic Schwann cells. Architecturally, the tumors differed from conventional schwannoma and nonplexiform cellular schwannomas by their lack of both well-formed capsules and degenerative changes. Follow-up was available in all cases and ranged from 2 to 13.6 years. All tumors recurred locally and were treated by local resections. With the exception of one child lost to follow-up at 25 months, all the children are alive and free of disease. Our data combined with cases previously reported by Meis-Kindblom and Enzinger show a childhood peripheral nerve tumor unassociated with type 1 neurofibromatosis, occurring most commonly in infants, often presenting as a congenital tumor and, though prone to local recurrence, having no metastatic potential. The behavior is that of a benign tumor, although its often rapid growth, hypercellularity and increased mitotic activity, sometimes locally aggressive behavior, and difficulties encountered in obtaining tumor-free margins are unsettling to pathologist and clinician alike. These features may lead to a misdiagnosis of malignancy, which could result in harmful overtreatment.

Antral hyperplastic polyp causing intermittent gastric outlet obstruction: case report.

BACKGROUND: Hyperplastic polyps are the most common polypoid lesions of the stomach. Rarely, they cause gastric outlet obstruction by prolapsing through the pyloric channel, when they arise in the prepyloric antrum. CASE PRESENTATION: A 62-year-old woman presented with intermittent nausea and vomiting of 4 months duration. Upper gastrointestinal endoscopy revealed a 30 mm prepyloric sessile polyp causing intermittent gastric outlet obstruction. Following submucosal injection of diluted adrenaline solution, the polyp was removed with a snare. Multiple biopsies were taken from the greater curvature of the antrum and the corpus. Rapid urease test for Helicobacter pylori yielded a negative result. Histopathologic examination showed a hyperplastic polyp without any evidence of malignancy. Biopsies of the antrum and the corpus revealed gastritis with neither atrophic changes nor Helicobacter pylori infection. Follow-up endoscopy after a 12-week course of proton pomp inhibitor therapy showed a complete healing without any remnant tissue at the polypectomy site. The patient has been symptom-free during 8 months of follow-up. CONCLUSIONS: Symptomatic gastric polyps should be removed preferentially when they are detected at the initial diagnostic endoscopy. Polypectomy not only provides tissue to determine the exact histopathologic type of the polyp, but also achieves radical treatment.

Hemangiopericytoma in the central nervous system: treatment, pathological features, and long-term follow up in 38 patients.

OBJECT: The authors reviewed the Mayo Clinic experience with the treatment of hemangiopericytoma in the primary central nervous system (CNS). METHODS: A retrospective study of all patients at the Mayo Clinic revealed 38 who had been treated for hemangiopericytoma in the CNS. Twenty of these patients were diagnosed in the decade between 1990 and 2000; 18 were initially diagnosed and underwent surgery before 1990. In the patients treated since 1990, the 5-year Kaplan-Meier survival rate was 93%. The 5-year disease-free survival rate was 89%. Sixty percent of patients treated with the aid of stereotactic radiosurgery for recurrent disease were alive 4.4 years after their initial treatment. Salvage chemotherapy was not effective. No survival benefit was detected inpatients who had received initial adjuvant external-beam radiation therapy. High-grade tumors recurred 6.7 years earlier than did low-grade lesions (p = 0.004). CONCLUSIONS: The 5-year survival rate in patients with hemangiopericytoma of the CNS has improved at the authors' institution during the last 10 years. Although the reason for this is not entirely clear, the authors suspect that the improved treatment of patients with cancer, a 0% intraoperative mortality rate, and the use of radiosurgery in the treatment of recurrent disease all likely contribute. High-grade tumors recurred statistically significantly earlier than low-grade lesions. Current chemotherapies are ineffective in the treatment of hemangiopericytoma of the CNS.

Glomangioma of the hip.

BACKGROUND: Glomus tumors may occur in any region of the body, but they are very rare in the hip. OBJECTIVE: To present the eighth reported case of a glomus tumor of the hip up to date. METHODS: This is a case report and a literature review. RESULTS: A 68-year-old man presented with severe pain and tenderness in the right hip, especially on palpation and in the sitting position. On physical examination, there was a soft palpable subcutaneous mass and severe tenderness in the right hip. Ultrasound revealed a hypervascular subdermal mass that was 2 cm in diameter. The lesion arose from the dermis and extended into the subcutaneous tissue. It was totally excised under local anesthesia. The histopathologic diagnosis was a glomangioma. The patient has been symptom free in the 2 months of follow-up. CONCLUSIONS: Glomus tumors should be kept in mind in the differential diagnosis of painful subdermal mass. Surgical excision of the lesion with a sufficient margin of surrounding normal tissue not only achieves the exact diagnosis but also results in adequate treatment. In case of the presence of malignant features, a wide excision is needed with a close follow-up of patient for regional or distant metastases.

p53 in nonneoplastic central nervous system lesions: an immunohistochemical and genetic sequencing study.

OBJECTIVE: Immunostaining for p53 commonly is considered a marker of neoplasia. Previous studies of nonneoplastic processes have yielded conflicting results. METHODS: To test the assumption that p53 immunoreactivity indicates neoplasia, we examined 60 formalin-fixed, paraffin-embedded biopsies of nonneoplastic central nervous system lesions, including gliosis (n = 12), infarction (n = 9), demyelinating disease (n = 23), progressive multifocal leukoencephalopathy (n = 11), and herpes simplex virus encephalitis (n = 5). Diffuse astrocytomas (n = 50) of World Health Organization Grades 2 to 4 also were studied, as were six control autopsy brains. The avidin-biotin-peroxidase complex method was used with commercially available monoclonal antisera to both p53 (clone DO7; Dako, Carpinteria, CA) and mdm2 (Dako), a protein known to stabilize p53. Two samples of each nonneoplastic lesion also were subjected to deoxyribonucleic acid isolation, amplification, and sequencing of exons 5 to 8 of TP53. RESULTS: Although it was low level in most instances, p53 immunoreactivity was noted in all but normal control samples. In reactive lesions, staining was largely observed in astrocytes and histiocytes. Scant oligodendroglia also were labeled in demyelinating disease. The progressive multifocal leukoencephalopathy samples revealed exceptionally strong staining in astrocytes and infected oligodendrocytes. Staining also was noted in occasional endothelial cells and neurons, and in rare lymphocytes. Immunoreactivity for mdm2, studied only in nonneoplastic lesions, was moderate to strong in all cases and limited to reactive astrocytes and histiocytes. No TP53 mutations were noted in the nonneoplastic lesions studied. To some extent, all astrocytomas exhibited p53 immunopositivity, particularly high-grade lesions. CONCLUSION: p53 immunoreactivity is not limited to astrocytomas, but it can be observed in lesions that often are mistaken for glioma. No TP53 mutations accompany p53 expression in nonneoplastic lesions, and mdm2 may be responsible for persistence of p53 expression in these processes.

Unusual case of extradural choroid plexus papilloma of the sacral canal. Case report.

An unusual case of a sacral, extradural choroid plexus papilloma involving the S1-3 level is described. This 50-year-old woman presented with a 4-month history of pain involving her right buttock, perineum, and leg. Contrast-enhanced magnetic resonance (MR) imaging of the spine revealed a well-defined, mildly enhancing sacral canal mass at the S1-3 level; its appearance was consistent with that of a benign tumor. Intraoperatively, the lesion was found to be extradural in location and was entwined among nerve roots in the sacral canal. Microscopic examination of the gross totally resected tumor revealed typical features of a choroid plexus papilloma. Despite performing a thorough neuroimaging workup (craniospinal contrast-enhanced MR imaging) for an intracranial or spinal primary mass, none was found. The choroid plexus appeared entirely normal; however, both a cavum septum pellucidum and a cavum vergae were noted. Extraneural choroid plexus papilloma, specifically intrasacral, extradural choroid plexus papilloma has not been previously reported. The present example is thought to have arisen either from ectopic choroid plexus tissue or perhaps by metaplasia from ependymal rests.

Metastatic papillary craniopharyngioma: case study and study of tumor angiogenesis.

We report a case of suprasellar papillary craniopharyngioma metastatic to the temporoparietal region 2 years after its initial resection. The literature documents examples of craniopharyngioma recurrences along the surgical tract, as well as remote ipsi- and contralateral metastases via cerebrospinal fluid seeding. Ours is the second report of a craniopharyngioma of papillary type to exhibit metastatic behavior. The tumor spread opposite the side of craniotomy. Although a rare occurrence, it confirms the limited capacity of histologically benign craniopharyngiomas to undergo meningeal seeding, likely the result of surgical manipulation. Immunohistochemical demonstration of increased microvascular density and vascular endothelial growth factor expression, as well as a high vascular endothelial growth receptor (VEGFR2) signal by in situ hybridization, suggests that tumor vascularity facilitated angiogenesis and may have been involved in the establishment and growth of the metastatic deposit.

Primary epithelioid sarcoma of the dura: case report.

OBJECTIVE AND IMPORTANCE: Epithelioid sarcomas are rare mesenchymal neoplasms that occur most often in the extremities of young adults. Despite isolated reports of epithelioid sarcomas arising in the head and neck region, these lesions have not been described previously, to our knowledge, in the central nervous system. CLINICAL PRESENTATION: We present the case of an 18-year-old woman with a unique dural sarcoma that arose in the right frontotemporal region. As visualized on magnetic resonance imaging studies, the 4.5-cm tumor focally traversed the cranium to penetrate the galea, the temporal muscle, and subcutaneous tissue. No brain invasion was noted. INTERVENTION: Despite gross total removal and postoperative radiotherapy (59 Gy), a large recurrence was noted 5 months after surgery. Histologically, the partly necrotic tumor consisted of epithelioid and spindle cells showing widespread vimentin and variable cytokeratin as well as epithelial membrane antigen immunoreactivity. Ultrastructurally, the cohesive cells featured various organelles, intermediate filaments, junctions, and filopodia-containing intercellular spaces. CONCLUSION: With the inclusion of epithelioid sarcoma, the spectrum of central nervous system sarcomas continues to expand.

Dysembryoplastic neuroepithelial tumor of the midbrain tectum: a case report.

Dysembryoplastic neuroepithelial tumor (DNT) is a relatively new nosologic entity. First described in 1988, it is now included in the "neuronal and mixed neuronal-glial tumours" category in the revised 2000 World Health Organization (WHO) Classification of Tumours of the Nervous System. The collective experience of more than 300 reported cases indicates that, with only rare exceptions, DNTs are cerebral cortical lesions. At present, the actual incidence of extracortical DNT is unknown. We describe, the clinicopathologic features of the first tectal DNT. The patient was a 51-year-old man with a 2-month history of pulsatile headaches. On neurologic examination, the only abnormality was gait ataxia. Magnetic resonance imaging (MRI) demonstrated a midbrain tumor involving the tectum. It was hypointense on T1-weighted images and featured an iso- to hyperintense nodule at its center. The nodule showed enhancement upon contrast administration. No aqueductal obstruction or intraventricular extension of tumor was detected. The tumor was approached supratentorially and removed completely. The mucoid tumor was well demarcated from neural tissue. Histopathologically, it was a typical DNT, exhibiting a nodular pattern of growth with a "specific glioneuronal component." This case report documents the first DNT to arise in the midbrain tectum and focuses on the problem of diagnosing this uncommon tumor at extracortical sites.