Melanotic paraganglioma of the orbit: a case report

Orbital Paraganglioma: A Systematic Review

Purpose  The purpose of this study was to perform a systematic review of the literature on orbital paragangliomas, evaluating clinical presentation, diagnosis, management patterns, and prognosis. Methods  The systematic review was conducted based on the principles described in the Preferred Reporting Items for Systematic Reviews and Meta-Analysis. PubMed, Cochrane databases, Embase, and Web of Science were searched for articles related to orbital paragangliomas. Inclusion criteria included English language articles with original reports on human subjects. Data on clinical presentation, diagnosis, treatment, and prognosis were collected. Results  Twenty-seven articles met inclusion criteria (28 total patients). The mean patient age was 37.1 years (range, 3-75 years); 13 (46.4%) patients were male. The most common presenting symptoms were proptosis (89.2%), visual acuity changes (67.9%), and extraocular muscle restriction (64.2%). Lesions were most commonly intraconal (92.9%). Single modality therapy was employed in 19 patients (67.9%), including excision in 12 patients (42.9%) and exenteration in 5 patients (17.9%). Ten patients (35.7%) developed recurrence, and there was a 92.9% survival rate (mean follow-up, 29 months). Conclusion  Orbital paragangliomas are rare tumors with an excellent prognosis. These lesions commonly present with proptosis, and are primarily managed surgically with simple excision, although exenteration and adjuvant radiation may be necessary for invasive tumors. This series is the largest and most comprehensive systematic review of orbital paragangliomas conducted to date.

Primary Melanotic Paraganglioma of Thyroid Gland: Report of a Rare Case With Clinicopathologic and Immunohistochemical Analysis and a Literature Review

Background:

Pigmented paraganglioma is a special type of paraganglioma, and it is rare in the thyroid.

Case Presentation:

We report a case of a 41-year-old woman who had complained of a mass in the thyroid gland. Histology revealed tumor cells arranged in a nest-like or organoid pattern, separated by delicate fibrovascular septa. Two distinct components were observed. In the first, which constituted the majority of the tumor cells, no pigments were observed. In the second, a few cells with pigment showed intercellular substance, but the structure was unclear. Using immunohistochemistry, cells in the first component were confirmed to be diffuse strong positive for synaptophysin, but negative for chromogranin A, pan-cytokeratin, calcitonin, and thyroglobulin. About 1% of tumor cells were stained by Ki-67. In the margins of the tumor, a few cells were observed to be positive for HMB-45 and Melan A after bleaching by oxalic acid. The stromal cells were positive for S-100. Using electron microscopy, a few cells containing many round melanin bodies with greater electron density granules of nonuniform size were observed. The diagnosis of primary melanotic paraganglioma of the thyroid gland was made.

Conclusion:

Primary melanotic paraganglioma of the thyroid gland is a rare, low malignant potential tumor. To the best of our knowledge, this is the first case described.

Somatic RET mutation in a patient with pigmented adrenal pheochromocytoma

Pheochromocytomas (PCC) and paraganglioma (PGL) are rare neuroendocrine tumors arising from chromaffin cells of the neural crest. Mutations in the RET-proto-oncogene are associated with sporadic pheochromocytoma, familial or sporadic medullary thyroid carcinoma (MTC) and multiple endocrine neoplasia type 2. In the past, only few cases of pigmented PCCs, PGLs, and one case of pigmented MTC have been reported in the literature. Herein, we present the case of a 77-year old woman with a history of Tako-tsubo-cardiomyopathy and laboratory, as well as radiological, high suspicion of pheochromocytoma, who underwent left-sided adrenalectomy. The 3 cm tumor, which was located on the upper pole of the left adrenal, appeared highly pigmented with dark red to black color. Histologic examinations revealed highly pleomorphic cells with bizarre, huge hyperchromatic nuclei, that immunohistochemically were positive for chromogranin A and synaptophysin, focally positive for HMB45 and negative for melan A. These clinical and pathological features led to the diagnosis of the rare variant of a melanotic 'black' pheochromocytoma. In our case a somatic RET mutation in exon 16 (RET c.2753T>C, p.Met918Thy) was detected by targeted next generation sequencing. In summary, this case represents a rare variant of catecholamine-producing tumor with distinct histological features. A potential relationship between the phenotype, the cellular origin and the genetic alterations is discussed.

LEARNING POINTS

Pheochromocytoma is a rare neuroendocrine tumor.Pigmentation is seen in several types of tumors arising from the neural crest. The macroscopic black aspect can mislead to the diagnosis of a metastasis deriving from a malignant melanoma.RET mutation are seen in catecholamine and non-catecholamine producing tumors of the same cellular origin.

A rare case of extra-adrenal pheochromocytoma localized to the ovary and detected via abdominal computed tomography angiography

Extra-adrenal pheochromocytomas are rare tumors that originate from the chromaffin tissue of the sympathetic nervous system. Ovarian extra-adrenal pheochromocytoma is even more rare. The present study reports a rare case of an extra-adrenal pheochromocytoma that was localized to the right ovary, but was gynecologically asymptomatic. Computed tomography angiography (CTA) detected the tumor and indicated that it was well defined, highly vascularized and obtained its blood supply from the right ovarian artery. This is the second case of ovarian extra-adrenal pheochromocytoma reported in the literature, and the first description of the CTA manifestations in the ovary. Gynecologists and radiologists should consider the possibility that an ovarian mass could be an extra-adrenal pheochromocytoma, which would allow time to prepare appropriately for the surgical removal of the mass.

Paragangliomas: update on differential diagnostic considerations, composite tumors, and recent genetic developments

Recent developments in molecular genetics have expanded the spectrum of disorders associated with pheochromocytomas (PCCs) and extra-adrenal paragangliomas (PGLs) and have increased the roles of pathologists in helping to guide patient care. At least 30% of these tumors are now known to be hereditary, and germline mutations of at least 10 genes are known to cause the tumors to develop. Genotype-phenotype correlations have been identified, including differences in tumor distribution, catecholamine production, and risk of metastasis, and types of tumors not previously associated with PCC/PGL are now considered in the spectrum of hereditary disease. Important new findings are that mutations of succinate dehydrogenase genes SDHA, SDHB, SDHC, SDHD, and SDHAF2 (collectively "SDHx") are responsible for a large percentage of hereditary PCC/PGL and that SDHB mutations are strongly correlated with extra-adrenal tumor location, metastasis, and poor prognosis. Further, gastrointestinal stromal tumors and renal tumors are now associated with SDHx mutations. A PCC or PGL caused by any of the hereditary susceptibility genes can present as a solitary, apparently sporadic, tumor, and substantial numbers of patients presenting with apparently sporadic tumors harbor occult germline mutations of susceptibility genes. Current roles of pathologists are differential diagnosis of primary tumors and metastases, identification of clues to occult hereditary disease, and triaging of patients for optimal genetic testing by immunohistochemical staining of tumor tissue for the loss of SDHB and SDHA protein. Diagnostic pitfalls are posed by morphological variants of PCC/PGL, unusual anatomic sites of occurrence, and coexisting neuroendocrine tumors of other types in some hereditary syndromes. These pitfalls can be avoided by judicious use of appropriate immunohistochemical stains. Aside from loss of staining for SDHB, criteria for predicting risk of metastasis are still controversial, and "malignancy" is diagnosed only after metastases have occurred. All PCCs/PGLs are considered to pose some risk of metastasis, and long-term follow-up is advised.

Pigmented paraganglioma of the kidney: a case report

Paragangliomas are rare neoplasms arising from undifferentiated cells of the primitive neural crest. We report a case of a 57-year-old patient with renal pigmented paraganglioma that was an incidental finding. Histopathological examination showed typical morphology of paraganglioma, as well as the unusual feature of large amounts of pigment in the cytoplasm of the tumor cells which was confirmed by bleached Fontana-Masson. Electron microscopy showed abundant, pleomorphic electron-dense granules consistent with neuromelanin. The tumor cells were positive for CD56 and chromogranin A, negative for HMB-45. The unique morphologic appearance represents divergent differentiation from neural crest. To our knowledge, the present case represents the first example of pigmented paraganglioma of the kidney.

Leiomyomatoid angiomatous neuroendocrine tumor (LANT) of the pituitary: a distinctive biphasic neoplasm with primitive secretory phenotype and smooth muscle-rich stroma

We describe a hitherto undocumented variant of dimorphic pituitary neoplasm composed of an admixture of neurosecretory cells and profuse leiomyomatous stroma around intratumoral vessels. Radiologically perceived as a macroadenoma of 3.8 cm in diameter, this pituitary mass developed in an otherwise healthy 43-year-old female. At the term of a yearlong history of amenorrhea and progressive bitemporal visual loss, subtotal resection was performed via transsphenoidal microsurgery. Discounting mild hyperprolactinemia, there was no evidence of excess hormone production. Histologically, solid sheets, nests and cords of epithelial-looking, yet cytokeratin-negative cells were seen growing in a richly vascularized stroma of spindle cells. While strong immunoreactivity for NCAM, Synaptophysin and Chromogranin-A was detected in the former, the latter showed both morphological and immunophenotypic hallmarks of smooth muscle, being positive for vimentin, muscle actin and smooth muscle actin. Architectural patterns varied from monomorphous stroma-dominant zones through biphasic neuroendocrine-leiomyomatous areas, to pseudopapillary fronds along vascular cores. Only endothelia were labeled with CD34. Staining for S100 protein and GFAP, characteristics of sustentacular cells, as well as bcl-2 and c-kit was absent. Except for alpha-subunit, anterior pituitary hormones tested negative in tumor cells, as did a panel of peripheral endocrine markers, including serotonin, somatostatin, calcitonin, parathormone and vasoactive intestinal polypeptide. Mitotic activity was absent and the MIB-1 labeling index low (1-2%). While assignment of this lesion to any established neoplastic entity is not forthcoming, we propose it is being considered as a low-grade neuroendocrine tumor possibly related to null cell adenoma.

Orbital paraganglioma: report of a rare case

CASE REPORT

Paragangliomas of the orbit are extremely rare tumors. We report a well-documented case of orbital paraganglioma in a 45-year-old man who presented with proptosis and decreased vision. The patient underwent complete excision of the tumor with preservation of orbital structures. There was total regression of symptoms after surgery and vision was well maintained.

COMMENTS

Radiological and pathological features are described and differential diagnoses of this entity are discussed.

Perivascular epithelioid cell tumor of the orbit: a case report and review of the literature

We present a unique case of a perivascular epithelioid cell tumor (PEComa) in the orbit of a 9-year-old female patient. The entity of PEComas has been described only recently. Characteristic histologic features and an immunohistochemical profile of negativity for epithelial markers and positivity for melanogenesis-related markers define the tumors. In children and young adults, this tumor has a predilection for the falciform ligament and ligamentum teres of the liver. It is associated with, but not exclusive to, tuberous sclerosis. To the best of our knowledge, this is the first reported case of a PEComa of the orbit in a child or adult. The main differential diagnoses for this melanin pigment-producing lesion include melanoma and pigmented paraganglioma. The histologic features, immunohistochemical profile, ultrastructural studies, and molecular studies led us to favor a diagnosis of PEComa. The prognosis of this entity is undetermined due largely to the small number of reported cases.

Pigmented “Black” Pheochromocytoma of the Adrenal Gland: A Case Report and Review of the Literature

A pigmented “black” mass was discovered incidentally in a 72-year-old woman. The tumor, which was detected near the upper pole of the left kidney, was cystic and intensely black throughout with the presence of abundant, coarse, dark brown to black pigment granules. Histologic examination showed a proliferation of monomorphous neoplastic cells arranged in a typical zellballen growth pattern. These features indicated a diagnosis of pheochromocytoma. Immunostains for chromogranin A, synaptophysin, and neuron-specific enolase were positive. The immunostain for HMB-45 was negative. Electron microscopy showed neurosecretory-type granules and larger pleomorphic granules, which were considered most consistent with neuromelanin, a waste product of catecholamine metabolism. The evidence of melanin or melanin-like pigment in the adrenal gland has been described in only 10 cases in the literature and is always a microscopic finding. The case reported here is unique for the characteristic black macroscopic appearance and the abundance of pigment.

Paraganglioma of the urinary bladder: a lesion that may be misdiagnosed as urothelial carcinoma in transurethral resection specimens

Paraganglioma of the urinary bladder is a rare tumor with characteristic histologic and immunohistochemical features. However, in our experience, it may be misdiagnosed as urothelial cancer because of 1) its frequent involvement of the muscularis propria; 2) morphology that may suggest urothelial cancer in transurethral resection specimens, particularly if there are artifactual changes induced by that procedure; 3) failure of pathologists to include it in their differential diagnosis when evaluating a bladder tumor; and 4) only a minority of the cases are associated with symptoms that might prompt consideration of the diagnosis. Distinction between paraganglioma and urothelial cancer is important because of likely different therapeutic options. In this report, we describe our experience with the histopathology of paragangliomas of the urinary bladder with emphasis on the histologic features that have led to their being misdiagnosed as conventional urothelial cancer and, most importantly, those that will help pathologists recognize this rare tumor of the bladder. Fifteen cases of paraganglioma of the urinary bladder were studied, 11 of them consult cases. They affected patients (8 male, 7 female) with a mean age of 49.5 years; only two had symptoms suggestive of the diagnosis, including hypertension during cystoscopy and episodic headache. Three consult cases were submitted with a diagnosis of "transitional cell carcinoma" and 4 with a diagnosis only of "bladder tumor." Histologically, "zellballen" and diffuse patterns were present in 12 (80%) and 3 (20%) of the cases. A delicate fibrovascular stroma was obvious in 14 (93%) cases. Other patterns included irregular nests and pseudorosette formation. Tumor necrosis, significant cautery artifact, and muscularis propria invasion were present in 1 (7%), 3 (20%) cases, and 10 (67%) cases, respectively. All 15 tumors were composed of large polygonal cells with abundant granular cytoplasm. Focal clear cells were present in 3 (20%). The nuclei were mostly uniform, although occasional pleomorphic nuclei were seen in 6 (40%) cases, and 2 (13%) had frequent pleomorphic nuclei. Mitoses were rare overall, and no abnormal mitotic figures were found. The major histologic features that led to misdiagnosis included a diffuse growth pattern, focal clear cells, necrosis, and muscularis propria invasion, with significant cautery artifact compounding the diagnostic problems. Immunohistochemically, 2 of 2 tumors were positive for neuron-specific enolase, 9 of 10 tumors for chromogranin, and 2 of 3 tumors for synaptophysin; 3 of 3 tumors were negative for cytokeratin and 1 of 1 tumor negative for HMB-45. Paraganglioma of the urinary bladder may be misdiagnosed as urothelial cancer, but a careful search for the characteristic histologic features and, if necessary, supportive immunohistochemical studies, should lead to a correct diagnosis.

Ileal Intussusception Due to Intestinal Metastases from Primary Malignant Melanoma of the Lung

Primary malignant melanoma of the lung (PMML) is an uncommon tumor with very few cases reported in the literature that satisfy the required criteria to establish a primary bronchial origin. We report a case of a 44-year-old man with acute abdominal distress and a right pulmonary roentgenographic opacity. A cranial-thoracic-abdominal CT scan confirmed the presence of a pulmonary nodule with bilateral cerebral metastases and marked dilatation of intestinal loops. At laparotomy an ileal intussusception was noted and an ileal resection was done. The resected intestinal segment contained three endoluminal polypoidal formations. Histological and immunohistochemical analyses showed the presence of multiple sites of melanoma. These lesions as well as the brain lesions clearly appeared metastatic. The patient underwent further evaluation to identify a primary site of melanoma; bronchoscopy was performed with biopsy of the pulmonary nodule. Pathology revealed a neoplastic process of fusiform cells, with focal presence of melanic inter- and extracellular pigment. The immunohistochemical analysis confirmed the diagnosis of PMML. We discuss the criteria for diagnosis and histogenesis of PMML along with this unusual presentation.

Pigmented ("black") extraadrenal paraganglioma

A pigmented ("black") extraadrenal paraganglioma was discovered incidentally in a 57-year-old woman during ultrasonography. The tumor was located in the retroperitoneum near the superior border of the right kidney. Results of preoperative fine-needle aspiration and intraoperative frozen sectioning of the resected jet-black tumor (13 cm in diameter, 225 g) were both interpreted as suspicious for malignant melanoma. Histomorphology and immunohistochemistry were diagnostic for paraganglioma. Electron microscopy showed numerous dense-core neurosecretory-type granules, as well as abundant, larger pleomorphic electron-dense granules; most were consistent with lipofuscin or neuromelanin. No melanosomes or premelanosomes were identified. Histochemical stains showed that the pigment most likely is neuromelanin, a nonenzymatic or oxidative waste product of catecholamine metabolism. Eighteen other examples of pigmented paragangliomas have been reported in various sites in the English literature during the last 12 years; most indicate the presence of melanosomes or premelanosomes using electron microscopy, whereas in a minority of cases the pigment has not been characterized rigorously. Common embryogenesis from neural crest may help explain the overlapping phenotype of melanocytes and cells of paraganglioma.

Primary melanoma of the lung: a clinicopathologic and immunohistochemical study of eight cases

Primary malignant melanoma of the lung (PMML) is an uncommon neoplasm that may be confused with more conventional types of lung cancer. Although the previously proposed criteria for diagnosis, including the presence of an in situ component, are often difficult to satisfy, this lesion is characterized by a poor prognosis, ultimately leading to patient death. We report eight cases of PMML that presented as solitary, central endobronchial neoplasms, resulting in a picture that closely resembled carcinoid tumor or poorly differentiated non-small-cell carcinoma of the lung. The mean age at diagnosis was 51 years (range 45-71). The patients included one woman and seven men. The histologic growth pattern varied from organoid to fascicular and included epithelioid to spindled cells with hyperchromatic to vesicular nuclei, prominent eosinophilic nucleoli, and abundant eosinophilic to clear cytoplasm with occasional intranuclear cytoplasmic inclusions. A bronchial in situ component was present in four cases. Initial interpretations included carcinoid tumor, non-small-cell carcinoma, and malignant melanoma. Melanin was present in all neoplasms on hematoxylin and eosin staining, although very focally in one case, and was Fontana-Masson positive in all cases. Immunohistochemically, diffuse strong positivity for S-100, HMB-45, and vimentin was present in all seven tumors tested. All seven tumors were negative for cytokeratin, CAM 5.2, and chromogranin. Ultrastructural examination of the eighth case showed dysmorphic premelanosomes but no neurosecretory granules. None of the patients had disseminated disease at presentation, and all patients underwent surgical resection (seven lobectomies and one excision). In this series, primary malignant melanoma of the lung was characterized by an aggressive postoperative course, with five patients dying of metastatic disease from 4 to 32 months after resection (median 14 months). Two patients are alive with metastatic disease at 4 and 30 months after surgery, and the eighth patient is alive with no evidence of disease 108 months after surgery at last follow-up. Metastatic melanoma was identified in various sites, including the lungs, adrenal glands, liver, mesentery, brain, and bone. The cases herein presented indicate that PMML should be included in the differential diagnosis of primary bronchial tumors.

Pigmented extraadrenal paragangliomas. A clinicopathologic and immunohistochemical study of five cases

BACKGROUND

Pigmented extraadrenal paragangliomas are unusual neoplasms that have rarely been reported in the literature.

METHODS

The clinical, pathologic, and immunohistochemical features of five cases of pigmented extraadrenal paragangliomas were reviewed.

RESULTS

The patients were 2 women and 3 men within the ages of 17 and 56 years (mean age: 36.5). Two neoplasms were located in the lumbar spine, one in the urinary bladder, one in the anterior mediastinum, and one in the retroperitoneum. Clinically, one patient with spinal paraganglioma presented with symptoms of numbness and weakness of the lower extremities whereas the second patient had low back pain of several weeks' duration. The paraganglioma of the bladder occurred in a pregnant woman who had symptoms of dysuria and microscopic hematuria whereas the patient with an anterior mediastinal tumor presented with chest pain. No clinical history was obtained from the patient with the retroperitoneal tumor. None of the patients had a history of hypertension. Grossly, the tumors were described as well-circumscribed, soft, and slightly hemorrhagic, and measured from 2 to 9 cm in greatest dimension. Histologically, the five tumors displayed characteristics similar to those described in these tumors, mainly the presence of an organoid or zellballen growth pattern. In addition, they contained moderate amounts of intracellular melanin pigment that focally obscured the true nature of the lesion. Immunohistochemically, four cases were positive for chromogranin whereas S-100 protein was detected in the sustentacular cells in four cases. Follow-up information ranging from 6 months to 18 years for 3 patients revealed that the patients were alive and well without recurrence or metastasis. One patient with spinal paraganglioma was lost to follow-up, and the patient with mediastinal paraganglioma was a recent case and therefore the behavior of the paraganglioma could not be assessed.

CONCLUSIONS

The current study expands the morphologic spectrum of extraadrenal paragangliomas and emphasizes the need to consider these tumors in the differential diagnosis of pigmented neoplasms. These findings suggest that the presence of melanin pigment does not alter the behavior of these neoplasms.

Laryngeal mucosal malignant melanoma. A clinicopathologic, immunohistochemical, and ultrastructural study of four patients and a review of the literature

BACKGROUND

Primary laryngeal mucosal malignant melanomas are uncommon tumors that morphologically are readily confused with more common types of laryngeal cancer.

METHODS

Four cases of primary laryngeal mucosal malignant melanoma were identified from the files of the Otolaryngic Tumor Registry-Armed Forces Institute of Pathology. Clinical records were available for all four cases. Paraffin blocks or unstained slides were available for three of the four cases. The light microscopic features were evaluated in all cases. Immunohistochemistry was performed in three cases; electron microscopic analysis was performed in two cases. Follow-up data was available in three of the four cases.

RESULTS

The patients were all males and ranged in age from 35 to 84 years. The clinical presentations included hoarseness, hemoptysis, dysphagia, and airway obstruction, with complaints ranging from 1 to 8 months. The sites of involvement included the supraglottic larynx and the right true vocal cord. A history of cutaneous melanoma or of a melanoma of another site was not reported for any of the patients. Histologically, the tumors were invasive and composed of a pleomorphic epithelioid cell population of malignant cells. Malignant spindle-shaped cell could also be identified. The presence of melanin was identifiable by light microscopy in two cases; Fontana stains confirmed the presence of melanin in the other two. The immunohistochemical findings showed diffuse immunoreactivity with S-100 protein and HMB-45. There was no immunoreactivity with cytokeratin. The specimen of one patient demonstrated focal immunoreactivity with chromogranin. Electron microscopic features included the presence of premalonosomes or melanosomes. Total laryngectomy was the treatment of choice supplemented with radiotherapy. Follow-up information was available for three patients and all three died of metastatic disease within 36 months of diagnosis. Metastasis occurred to the brain, lungs, spine, and regional lymph nodes. The fourth patient was lost to follow-up.

CONCLUSIONS

Laryngeal mucosal malignant melanoma is an uncommon neoplasm that clinically and pathologically simulates more conventional types of laryngeal cancers. The light microscopic, immunohistochemical, and electron microscopic findings confirm the diagnosis. Aggressive management is indicated, as these tumors disseminate widely and are rapidly fatal.

Melanotic paraganglioma of the posterior mediastinum

A melanotic paraganglioma occurred in a 57-year-old woman, located in the left paravertebral space of the upper mediastinum. It was totally resected. During a 5 year follow up period neither tumour recurrence nor metastasis were observed. Histological examination of the tumour revealed a paraganglioma with monomorphous chief cell like elements which were arranged in a "zellballen" pattern. Immunohistochemical results also were in accordance with the diagnosis since neuron-specific enolase, chromogranin and synaptophysin were found in tumour cells whereas keratin was not. Additionally, neurosecretory granules were found in tumour cells during electron microscopy. A peculiar feature of the tumour was its strong pigmentation due to melanin located within the tumour cells and tumour associated melanophages. The simultaneous expression of functional properties of two different neural crest derived cells in one tumour stresses the close relationship between all neural crest elements and is in accordance with the observation of other melanotic, non-melanomatous tumours.

Melanotic cerebral ganglioglioma: evidence for melanogenesis in neoplastic astrocytes

A composite melanotic glial-ganglionic tumor was resected from a 17-year-old girl who presented with a 5-year history of epilepsy. Grossly, the tumor was partly cystic, partly solid, located superficially in the temporal lobe. Histologically, its glial component was composed of spindle and pleomorphic cells, including tumor giant cells, which were associated with Rosenthal fibers, eosinophilic granular bodies and marked desmoplasia. The cells had immunohistochemical and ultrastructural features of astrocytes, and some were invested by incomplete basal lamina. Thus, the tumor had many features in common with pleomorphic xanthoastrocytoma. However, its most striking feature was the presence of melanin pigment in numerous neoplastic cells. Immunoelectron microscopy revealed glial fibrillary acidic protein-positive intermediate filaments in tumor cells bearing melanosomes and premelanosome, proving their astrocytic nature. This case demonstrates, for the first time, melanosomal melanogenesis in human cells with astrocytic phenotype, and provides additional evidence for the ability of central neuroepithelial cell derivatives to produce melanin.