Immunocytochemistry of paragangliomas--value of staining for S-100 protein and glial fibrillary acid protein in diagnosis and prognosis

Laparoscopic resection of a paraganglioma in the greater omentum mimicking a peripancreatic neoplasm: a case report

A paraganglioma is a tumor originating in the sympathetic or parasympathetic nervous system. Its diagnosis may sometimes be confusing if it occurs in an atypical site. We described herein a case of a peripancreatic paraganglioma originating in the greater omentum. An asymptomatic, 61-year-old, female patient was referred to our hospital for detailed examination of a peripancreatic mass detected incidentally on computed tomography (CT). The differential diagnosis was a neuroendocrine neoplasm (NEN), and a biopsy using EUS-FNA was performed. Histologically, the tumor cells showed proliferation in solid cell nests and were positive for CD56, chromogranin A, and synaptophysin. These findings and the hypervascularity of the tumor on imaging studies were compatible with NEN. Since the imaging studies did not clearly demonstrate the continuity of the tumor with the pancreas, laparoscopic tumor resection without a pancreatectomy and sampling of the enlarged peripancreatic lymph nodes were planned as treatment. The absence of continuity with the pancreas was later confirmed by intraoperative observation, and the resection was carried out as planned. The resected tumor was pathologically considered as NEN at first in agreement with the preoperative diagnosis. However, several histological findings (such as a zelleballen-like growth pattern, pseudo-inclusion, and strong nuclear atypia compared with the cells' proliferative ability) were atypical for NEN, and paraganglioma was included in the differential diagnosis. Additional immunostainings of S-100 and AE1/AE3 were performed, leading to the final diagnosis of paraganglioma. Paragangliomas should be included in the differential diagnosis of an intraperitoneal mass of uncertain identity with hypervascularity.

Differential diagnosis and unusual diffuse cytokeratin expression in renal paraganglioma: A case report

Paraganglioma is a rare neuroendocrine tumor arising from undifferentiated cells of the primitive neural crest. We report a case of renal paraganglioma in a 67-year-old patient. Computed tomography demonstrated a solid mass in the middle and lower pole of the right kidney. Sonography revealed an enlarged right kidney with an irregular shape but distinct border. Renal cell carcinoma was diagnosed provisionally; the tumor was completely resected and submitted for pathological examination. Unexpectedly, histopathology and immunohistochemistry confirmed paraganglioma arising from the renal parenchyma. In this study, we report the exceptional occurrence of Paired box gene 8 (PAX-8) expression in a renal paraganglioma. In addition, we demonstrated diffuse cytokeratin positivity in this renal paraganglioma. Although our report of a paraganglioma originating from the kidney is not unique, our finding expands the known immunophenotypic spectrum of this tumor. The awareness of the possible occurrence of cytokeratin diffuse positivity in paraganglioma is relevant to avoiding misdiagnosis of paraganglioma.

Immunohistochemical distinction of paragangliomas from epithelial neuroendocrine tumors-gangliocytic duodenal and cauda equina paragangliomas align with epithelial neuroendocrine tumors

Distinction of paraganglioma (PGL) from epithelial neuroendocrine tumors (NETs) can be difficult as they can mimic each other by nested architecture and expression of neuroendocrine markers. In this study, we examined differential diagnostic markers in 262 PGLs (142 adrenal pheochromocytomas and 120 extra-adrenal PGLs), 9 duodenal gangliocytic PGLs and 3 cauda equina PGLs, and 286 NETs (81 GI, 78 pancreatic, 42 thoracic, 37 medullary thyroid carcinomas, and 48 high-grade NETs including 32 small cell carcinomas of lung). While keratin expression was nearly uniform in NETs with the exception of few tumors, extensive keratin expression was seen in only one PGL (<1%) and focal expression in 5% PGLs. GATA3 was present in >90% of PGLs but only in 2% of NETs, usually focally. Tyrosine hydroxylase (TH) was expressed in >90% of adrenal, abdominal, and thoracic PGLs but only in 37% of head and neck PGLs, reflecting their variable catecholamine synthesis. Focal or occasional extensive TH-expression was detected in 10% of NETs. CDX2 was a helpful discriminator seen in 28% of pancreatic and most GI NETs but in no PGLs. SOX10 detected sustentacular cells in 85% of PGLs and 7% of NETs, whereas GFAP detected sustentacular cells mainly in PGLs of neck and was absent in NETs. Duodenal gangliocytic PGLs (n = 9) and all cauda equina PGLs (n = 3) expressed keratins, lacked GATA3, showed no or minimal TH expression as some NETs, and contained SOX10 and S100 protein-positive spindle cells negative for GFAP. Ganglion-like epithelioid cells were keratin-positive and negative for TH and SOX10 differing from true ganglion cells. We conclude that duodenal gangliocytic and cauda equina PGLs have a NET-like immunoprofile and differ from ordinary PGLs. NETs can be distinguished from PGLs by their expression of keratins and general lack of GATA3, TH, and GFAP-positive sustentacular cells, and sometimes by expression of CDX2 or TTF1.

Catecholamine-Synthesizing Enzymes in Pheochromocytoma and Extraadrenal Paraganglioma

In chromaffin cells, tyrosine hydroxylase (TH), aromatic L-amino acid decarboxylase (AADC), dopamine β-hydroxylase (DBH), and phenylethanolamine N-methyltransferase (PNMT) are mainly involved in catecholamine synthesis. In this study, we evaluated the association between the status of catecholamine-synthesizing enzymes and histopathological features of pheochromocytoma and extraadrenal paraganglioma with special emphasis upon their postoperative clinical behavior. Immunohistochemical evaluation of TH, DBH, AADC, PNMT, Ki 67, and S-100 was performed in 29 pheochromocytoma and 10 extraadrenal paraganglioma and one lymph node harboring metastatic pheochromocytoma. Among these cases, metastasis was subsequently developed in three cases. Urinary normetanephrine (U-NM) levels were significantly higher in clinical metastatic cases than non-metastatic ones. Ki 67 labeling index was significantly higher in both clinical metastatic cases and the Adrenal Gland Scaled Score (PASS) score of ≧ 4 cases than PASS < 4 cases, although this score was originally used in pheochromocytoma. H-score of AADC and DBH were significantly lower in PASS ≧ 4 cases than those with < 4 cases, and in the cases associated with intratumoral necrosis (n = 4), the presence of spindle shaped tumor cells (n = 4), and large nests of cells or diffuse growth (n = 5). Lower status of intratumoral AADC could be related to poor differentiation of tumor cells in both catecholamine production and morphology and could be related to aggressive biological behavior of both pheochromocytoma and extraadrenal paraganglioma.

Diagnosis and surgical treatment of retroperitoneal paraganglioma: A single-institution experience of 34 cases

The present study aimed at identifying the clinical, radiological and pathological characteristics of retroperitoneal paragangliomas, and determining the association between the tumor features and the prognosis of patients following surgery. A total of 34 patients with retroperitoneal paragangliomas, who underwent resection between November 1999 and December 2015, were included in the present retrospective study. The patients' demographics, clinical symptoms and signs, tumor functional status, surgical procedure, intraoperative results, tumor pathology, radiological results, and postoperative survival time were recorded and analyzed. Of the 34 patients, the most common type of presenting symptom was abdominal mass (46%), followed by hypertension (39%) and abdominal pain (32%). Functional tumors occurred in 20 patients (59%). Computed tomography (CT) and magnetic resonance imaging revealed soft-tissue masses, with marked enhancement in the arterial phase, indicative of retroperitoneal paragangliomas. The preoperative CT diagnostic accuracy rate between 2010 and 2015 was markedly improved, compared with that between 1999 and 2009. The tumors were primarily located close to the renal arteries and veins surrounding the abdominal aorta and inferior vena cava. With the exception of one malignant paraganglioma, the majority of paragangliomas were positive for chromogranin A, S-100 protein, vimentin and heat-shock protein 90, and exhibited decreased expression of Ki-67 antigen and insulin-like growth factor 2. All tumors were completely removed by surgery. Distant metastasis, but not tumor size, functional status and local invasion, was markedly associated with survival. The preoperative diagnostic accuracy rate of retroperitoneal paragangliomas may be improved by focusing on the predilection sites and CT characteristics. In addition, immunohistochemical markers were useful to determine tumor malignancy. Complete surgical resection was appropriate for all patients and postoperative survival time was identified to be associated with tumor metastasis.

Renal paraganglioma: report of a case managed by robotic assisted laparoscopic partial nephrectomy and review of the literature

We describe the pathological and clinical presentation of a rare case of renal paraganglioma occurring as an incidental left renal mass in a 58-year-old woman. The patient underwent robotic assisted laparoscopic partial nephrectomy, which is the first one in the literature.

Metastasis to left scapula with unknown primary: Approach to pathological diagnosis

Bony metastasis is a frequent occurrence in malignancy. However, the clinical presentation and pathological findings may sometimes be more in favor of a primary bone lesion. In such cases, immunochemistry has a very important role to play in reaching a final diagnosis. We present the case of a 35 year male patient who was investigated for a lytic lesion in the left scapula and was finally diagnosed with metastatic adenocarcinoma with the help of immunostaining.

Atypical Central Neurocytoma with Recurrent Spinal Dissemination over a Period of 20 Years: A Case Report and Review of the Literature

We present an unusual case of a late recurrent central neurocytoma that was rediagnosed as an ependymoma and neurocytoma in accordance with changes in histological classifications. Case Description. A 56-year-old male teacher presented with incomplete transverse syndrome due to several intradural extramedullary tumors at the level of lumbar vertebrae 1-3. The histological diagnosis at the time was atypical ependymoma. One year later, two additional tumors were removed at the L5-S1 vertebral level. For 12 years, the patient remained tumor free on followup. Fourteen years after the initial diagnosis, the patient presented with thoracic paresthesias due to two new extramedullary tumors in the C7-T1 and the T8-T9 vertebral levels. After complete removal of the tumors, a radiological survey revealed an intracranial lesion in the third ventricle. Five months later, an additional lesion recurrence was removed surgically. The most recent histological diagnosis revealed an atypical central neurocytoma. In retrospect, the previous tumors were reclassified as neurocytoma according to the additional immunohistochemistry evidence. Discussion. There is no standard adjuvant treatment regimen for atypical neurocytoma; therefore, the patient is currently under close followup. Modern histopathological diagnosis is essential in these cases. Potential routes for dissemination of the tumor should be considered upon first recurrence.

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.

Extrapulmonary small cell carcinoma: a clinicopathological study with identification of potential diagnostic mimics

AIMS

To evaluate the clinicopathological features of small cell carcinoma arising outside the lung.

METHODS AND RESULTS

Thirty-seven cases with a pathology diagnosis of extrapulmonary small cell carcinoma (EPSCC) were selected. The clinical notes were reviewed and tumour blocks were selected for a fresh haematoxylin and eosin (H&E) section and immunohistochemical stains. The most common tumour locations were cervix and bladder. Twenty-five cases (68%) were finally diagnosed as EPSCC, nine of which were found with coexisting non small cell carcinoma. Two cases (5%) were diagnosed as large cell neuroendocrine carcinoma (LCNEC) of the cervix. The remainder was classified as 10 poorly differentiated carcinomas (PDCs) (27%). Positive staining for thyroid transcription factor 1 (TTF-1) was noted in nine cases of EPSCC and in none of the cases of PDC (P = 0.034). Synaptophysin immunoreactivity was found in 20 cases of EPSCC and two cases of PDC with neuroendocrine differentiation (P = 0.002), as well as two cases of LCNEC. 34βE12 was positive in eight cases of SCC and two cases of PDC.

CONCLUSIONS

Based on this series, EPSCC may be overdiagnosed. Immunohistochemistry for TTF-1, used in combination with synaptophysin, may help to discriminate EPSCC from PDC.

Malignant pheochromocytomas and paragangliomas: a diagnostic challenge

INTRODUCTION

Malignant pheochromocytomas (PCCs) and paragangliomas (PGLs) are rare disorders arising from the adrenal gland, from the glomera along parasympathetic nerves or from paraganglia along the sympathetic trunk. According to the WHO classification, malignancy of PCCs and PGLs is defined by the presence of metastases at non-chromaffin sites distant from that of the primary tumor and not by local invasion. The overall prognosis of metastasized PCCs/PGLs is poor. Surgery offers currently the only change of cure. Preferably, the discrimination between malignant and benign PCCs/PGLs should be made preoperatively.

METHODS

This review summarizes our current knowledge on how benign and malignant tumors can be distinguished.

CONCLUSION

Due to the rarity of malignant PCCs/PGLs and the obvious difficulties in distinguishing benign and malignant PCCs/PGLs, any patient with a PCC/PGL should be treated in a specialized center where a multidisciplinary setting with specialized teams consisting of radiologists, endocrinologist, oncologists, pathologists and surgeons is available. This would also facilitate future studies to address the existing diagnostic and/or therapeutic obstacles.

Sox10-positive sustentacular cells in neuroendocrine carcinoma of the lung

AIMS

Sustentacular cells are found in approximately half of pulmonary carcinoid tumours. However, most studies of sustentacular cells have used the less-specific antibody to the S100 protein, and any correlation between the presence of sustentacular cells and other clinicopathological factors is unclear. The aim of this study was to analyse the significance of sustentacular cells in pulmonary neuroendocrine carcinomas (NECs).

METHODS AND RESULTS

A Sox10 antibody was used to investigate 113 pulmonary NECs. Sustentacular cells were observed in 66.7% of typical carcinoid (TC) and 58.3% of atypical carcinoid (AC) cases, but not in high-grade NECs. Sustentacular-rich tumours had a statistically significant correlation with peripheral locations. We found no statistical differences in age, gender, smoking history, overall survival, or the occurrence of lymph node metastasis. In all but one case, when sustentacular cells were present in the primary site, they were also present in the metastatic lymph nodes. The presence of sustentacular cells differed in morphological subtypes, with the spindle pattern being the most common subtype.

CONCLUSIONS

Sox10-positive sustentacular cells were observed in carcinoid tumours but not in high-grade NECs. Sustentacular-rich carcinoid tumours did not show a correlation with the occurrence of lymph node metastasis or survival. The sustentacular cells found differed in morphological subtypes.

Histologic and immunohistochemical characterization of pheochromocytoma in 6 cotton-top tamarins (Saguinus oedipus)

Pheochromocytomas are uncommon neoplasms of the adrenal medulla that are most frequently reported in rats and select mouse strains. In many cases, especially those in man, pheochromocytoma is associated with familial tumor syndromes, because of inherited mutations in a variety of proto-oncogenes and tumor suppressor genes. Nonhuman primates are valuable animal models for a variety of human diseases because of their similar anatomy and physiology; however, cases of pheochromocytomas have only rarely been reported in nonhuman primates. Herein, we characterize the gross, histologic, and immunohistochemical features of pheochromocytoma in 6 cotton-top tamarins (Saguinus oedipus). Pheochromocytomas represented 6 of 114 of the total causes of death in the studied population (5.3%) and corresponded to 16% of the total number of neoplasms. The average age of affected animals was 17.9 years. On histologic examination, all cases were defined by tight bundles, nests, and cords of neoplastic chromaffin cells. All cases had concurrent myocardial degeneration and fibrosis of varying severity and chronicity. Three of the cases (50%) also had hyalinization and medial thickening of coronary arteries consistent with hypertension. On immunohistochemical examination, 6 of 6 of the cases (100%) stained positively for chromogranin A, synaptophysin, N-CAM (or CD56), and protein gene product 9.5. None of the cases stained for glial fibrillary acidic protein. Pedigree analysis revealed inter-relatedness in 4 of 6 animals, with progenitor animals also affected with pheochromocytomas. The tumors in this population illustrate comparable histologic and immunohistochemical staining patterns with cases in other laboratory animals and humans, and, therefore, may indicate common underlying genetic alterations that precipitate tumor development.

Hereditary paraganglioma of the nasopharynx

Head and neck paragangliomas are rare neuroendocrine tumors derived from neural crest cells of parasympathetic ganglia or the widely dispersed neuroendocrine cells of the head and neck region. Paragangliomas of the sinonasal tract and nasopharynx are rare. The clinicopathologic features of this unique example of a hereditary, nasopharyngeal paraganglioma, and selective entities that are included in its differential diagnosis are presented.

Glia-like stem cells sustain physiologic neurogenesis in the adult mammalian carotid body

Neurogenesis is known to occur in the specific niches of the adult mammalian brain, but whether germinal centers exist in the neural-crest-derived peripheral nervous system is unknown. We have discovered stem cells in the adult carotid body (CB), an oxygen-sensing organ of the sympathoadrenal lineage that grows in chronic hypoxemia. Production of new neuron-like CB glomus cells depends on a population of stem cells, which form multipotent and self-renewing colonies in vitro. Cell fate mapping experiments indicate that, unexpectedly, CB stem cells are the glia-like sustentacular cells and can be identified using glial markers. Remarkably, stem cell-derived glomus cells have the same complex chemosensory properties as mature in situ glomus cells. They are highly dopaminergic and produce glial cell line-derived neurotrophic factor. Thus, the mammalian CB is a neurogenic center with a recognizable physiological function in adult life. CB stem cells could be potentially useful for antiparkinsonian cell therapy.

Sphenoid sinus paraganglioma: first reported case

Paragangliomas are uncommon tumors that present in the head and neck. Rarely, this benign tumor may occur in the nose and paranasal sinus. We report a case of paraganglioma involving the sphenoid sinus, discuss histologic characteristics, and review this tumor.

Malignant Pheochromocytoma

Malignant pheochromocytoma is a rare disease with a high mortality. Surgical resection is the only effective treatment if extensive metastatic disease is not present. However, differentiating between benign and malignant pheochromocytoma is impossible in the absence of locoregional invasion or distant metastasis. This diagnostic dilemma has several drawbacks, including later detection and treatment of recurrence than if malignancy is determined at the original operation. With emerging molecular markers of malignant disease, optimal extent and approach for surgical treatment and appropriate extent of follow up could be established based on specific tumor behavior and the need for additional systemic therapy.

Paraganglioma of the Ovary

Paraganglioma is one of the rarest neoplasms to involve the ovary, whether primary or metastatic, with only two previous reports. We describe three examples that occurred in patients 22, 58, and 68 years of age. Two patients had hypertension. Two tumors involved the left ovary and one the right ovary; they ranged from 8 to 22 cm, were solid, and were tan, brown, or yellow. One tumor was confined to the ovary; in the second case, there were tumor deposits on the posterior surface of the uterus and the contralateral ovary; in the other case, there was peri-aortic lymph node involvement and peritoneal deposits. In all cases, however, radiologic investigations did not reveal an alternative primary site. On microscopic examination, all three tumors showed a predominantly nested "zellballen" pattern with groups of cells surrounded by a vascular stroma. Tumor cells largely had abundant granular eosinophilic cytoplasm with, in 2 cases, focal clear cell areas. In 1 case, bizarre tumor giant cells were present. Immunohistochemically, all neoplasms were cytokeratin negative and diffusely positive with neuroendocrine markers. In 1 case, there was an S-100-positive population of sustentacular cells. Two cases were positive for inhibin, one focal and one diffuse, and the other was focally positive for calretinin. Electron microscopy performed in 2 cases revealed dense core neuroendocrine granules. One patient has been followed up for 15 years and is alive and well. Although metastatic spread from an undetected primary outside the ovary cannot be totally excluded for the 2 cases with extraovarian disease, we think that the neoplasms most likely represent primary ovarian paragangliomas. Because various neoplasms in the sex cord-stromal and steroid categories are likely to enter into the differential diagnosis, inhibin and calretinin positivity represents a significant potential diagnostic pitfall. The differential is broad and may include many other ovarian tumors, particularly those with an oxyphilic cell type. Possible theories of histogenesis of primary ovarian paraganglioma include an origin from extra-adrenal paraganglia in the region of the ovary or unidirectional differentiation within a teratoma.

Sustentaculoma

A case of a morphologically distinctive tumor of the adrenal medulla occurring in a 54-year-old woman is described. On microscopic examination, the tumor was well circumscribed and characterized by the presence of ill-defined, irregular nests of spindle cells with oval to elongated nuclei, tiny nucleoli, and abundant eosinophilic cytoplasm. The tumor was associated with a moderate infiltrate of lymphocytes and plasma cells with occasional lymphoid follicles. Necrosis, marked cellular atypia, and mitoses were absent. Immunohistochemical studies demonstrated the tumor cells to be strongly reactive for vimentin, S-100 protein, and CD56, and nonreactive for glial fibrillary acidic protein, chromogranin, synaptophysin, melanoma-associated antigens, and dendritic cell markers. Ultrastructural examination showed elongated cells with interdigitating cytoplasmic processes devoid of a basal lamina. No secretory granules were noted. The morphology, immunophenotype, and ultrastructure of this unique neoplasm suggest derivation from sustentacular cells of the adrenal medulla. We propose the designation "sustentaculoma" for this hitherto undescribed neoplasm of the adrenal gland.

Histopathology and immunohistochemistry of adrenal medullary tumors and paragangliomas

Paragangliomas arise from sympathetic or parasympathetic paraganglia and should now be defined by their site and type. The term pheochromocytoma is reserved for intra-adrenal tumors. This short review discusses the gross and microscopic features, the immunohistochemical profile, the problem of recognizing malignant potential, and the rare instances where a differential diagnosis has to be considered.

Use of S-100 and Chromogranin A Antibodies as Immunohistochemical Markers on Detection of Malignancy in Aortic Body Tumors in Dog

To define the characteristics of malignancy we performed routine histology and an immunohistochemical study on seventeen aortic body tumors in dogs. We essayed tumors using a panel of immunohistochemical markers: neuron specific enolase (NSE), chromogranin A (CrA) and S-100. Among 17 cases, the neoplastic cells were positive for NSE (17 cases, 100%), S-100 (9 cases, 53%), and CrA (8 cases, 47%), respectively. The sustentacular cells density and chief cell staining intensity were both inversely related to tumor grade. The most relevant data was consistent with a negative staining of S-100 correlated with absence or decreased number of sustentacular cells in tumors grade III. This report indicates that the immunohistochemical panel has utility for the diagnosis of chemodectoma and the negative staining to CrA and S-100 markers in tumors grade III expresses an indication of malignant behaviour of the tumor.

Plasminogen activator inhibitor-1 and transforming growth factor-beta 1 in carotid glomus and autonomic ganglia from spontaneously hypertensive rats

BACKGROUND

Baroreflex and chemoreflex mechanisms play an important role in the dynamic adjustments of circulation and ventilation during daily life. Recently, we have observed atrophy and marked fibrosis in carotid glomus (CG) from old patients with carotid atherosclerosis who died following stroke. However, a possible limitation to interpretation of the results in that study was the superposition of arterial hypertension, atherosclerosis and aging in the patients. Taking this into account, spontaneously hypertensive rats (SHR) were used in order to study the CG in an experimental model with only hemodynamic stress.

OBJECTIVE

To evaluate whether transforming growth factor-beta 1 (TGF-beta 1) and plasminogen activator inhibitor-1 (PAI-1) were involved in the extracellular matrix expansion in CG and autonomic ganglia (AG) in young, male, adult SHR.

METHODS

Male SHR (n = 10) and Wistar-Kyoto (WKY) rats (n = 10) were used. Systolic blood pressure (SBP) was measured monthly up to 8 months of age, when the animals were killed; then, CG and AG were excised and processed for light microscopy and immunohistochemistry (TGF-beta 1, PAI-1 and protein S100).

RESULTS

SBP was highly correlated (P < 0.01) with CG fibrosis (r = 0.90), AG fibrosis (r = 0.96) and neuron number (r = -0.97). PAI-1 and TGF-beta 1 in CG and AG were significantly increased (P < 0.01) in SHR.

CONCLUSION

Severe damage was observed in CG and AG in SHR, which was, in addition, correlated with SBP. These results suggest that permanent high blood pressure produces remarkable lesions in these structures, even when the animals are not old. In view of the fact that CG and AG are of utmost importance in the genesis of cardiocirculatory reflexes, they might be considered as 'target organs' in arterial hypertension.

Malignant retroperitoneal paraganglioma: case report and review of the literature

Paraganglioma is a rare neuroendocrine neoplasm observed in patients of all ages but it has not been characterized in children. The authors describe a retroperitoneal paraganglioma diagnosed by chance in an 11-year-old boy. Many aspects of retroperitoneal paraganglioma are still under investigation. The treatment of choice is radical resection. Surgery may be possible following chemotherapeutic debulking with cyclophosphamide, vincristine, and dacarbazine. 131I-MIBG radiotherapy has proved increasingly useful in reducing the pain associated with disseminated disease and also in facilitating surgical resection in cases that appear inoperable. Conventional radiotherapy is purely palliative and used to reduce the pain of bone metastases.

CGH and CD 44/MIB-1 immunohistochemistry are helpful to distinguish metastasized from nonmetastasized sporadic pheochromocytomas

The natural course of pheochromocytomas (PCC) cannot be predicted for certain on the basis of primary histology, their malignant character can only be confirmed by the occurrence of metastases during follow-up. Based on the recently proposed PASS score for evaluation we examined 37 adrenal (36 sporadic and one familial) and six sporadic extra-adrenal paragangliomas (all designated as pheochromocytomas) with a 'malignant histology' to find additional predictive factors. Drawing upon the follow-up (18 months to 12 years, mean 5.8 years) metastasized (n=20) and nonmetastasized (n=23) courses could be distinguished. Metastasized PCC revealed significantly (P=0.03) more copy number changes on comparative genomic hybridization (CGH) (mean 8.3) than nonmetastasized tumors (mean: 4.3). The most frequent chromosomal alterations were losses on 1p (75.6%) and 3q (44%). Both were detected with identical frequency in metastasized and nonmetastasized PCC. A gain on 17q (P=0.025) was significantly predominant in malignant courses and suggests similarities in the genetic origin and progression of PCC and neuroblastomas. The proliferative activity (MIB-1 score) of metastasized PCC (n=20) was found to be significantly higher in metastasized tumors (mean 12.8% vs mean 3.5%). In contrast, the semiquantitatively scored membrane-bound staining of CD 44-S was stronger in tumors without metastases (mean 2.1 vs mean: 0.25) during the follow-up period (P<0.01). Although the results correspond to the established weight differences the tumor weight does not appear to be an independent prognostic factor. Our study suggests that CD 44-S and MIB-1 immunostaining as well as the CGH results might complement the PASS score in predicting a metastasized course of PCC. Regardless of tumor weight, tumors with a 'malignant histology' are highly prone to metastasize when more than 5% of MIB1-positive nuclei are present or CD44-S immunostaining is negative, or both. PCC with 10 or more copy number changes on CGH must be referred to as malignant tumors.

Malignancy in pheochromocytomas. Review article

A catecholamine-secreting tumor arising from the chromaffin cells of the sympathoadrenal system was first termed pheochromocytoma by Poll in 1905. The term refers to the dysky (pheo) color (chromo) of the cut surface of the tumor when exposed to dichromate. Pheochromocytomas most commonly arise from the adrenal medulla. Extraadrenally located pheochromocytomas are called paragangliomas, and arise from the paraganglion system. An adrenal pheochromocytoma is usually a rounded, gray-white, firm tumor 3 to 5 cm in diameter. When larger, they can adhere to adjacent structures, although still not metastasizing. Most pheochromocytomas are benign. However, approximately 10% of these tumors metastasize. It is almost impossible to differentiate a benign from a malignant tumor only by histological criteria. Classically only metastasized tumors are considered malignant for certain. Many attempts have been made to find markers that would predict the future behavior of an unmetastasized pheochromocytoma. In this overview of malignancy in pheochromocytomas, different steps of the tumorigenesis and several markers associated with them are discussed.

February 2004: a 44-year-old man with a 2-year history of epistaxis

A 44-year old man presented with a 2-year history of epistaxis and a nodular lesion in the nasopharyngeal mucosa. Neuroimaging revealed a midline nasopharyngeal tumor extending through the skull base to the clivus. Following surgical resection, histological studies showed a paraganglioma, a tumor with a typical nesting pattern, abundant capillary network, and strong immunoreactivity for neuroendocrine markers. Paragangliomas of the head and neck are rare tumors, which may come to the neuropathologist's attention because of their propensity for intracranial spread. In particular, paragangliomas located in the nasopharynx may generate diagnostic difficulties, as they appear to have no connection with major paraganglia in the region. Morphologic criteria do not allow distinguishing between benign and malignant forms.

Paraganglioma of the nasal cavity: a case report

We describe the case of a 72-year-old woman presenting with a 1-year history of recurrent epistaxis and unilateral progressive nasal obstruction with associated rhinolalia resulting from the presence of a tumor mass occupying two-thirds of the right nasal cavity. Histopathologically, neoplastic cells or "chief cells" were arranged in well-defined nests, which had the classic alveolar or so-called "zellballen" pattern. Immunohistochemical studies highlighted the presence of S-100 protein-positive sustentacular cells located at the periphery of the clusters of chief cells. The chief cells showed a diffuse and intense positivity for neuron-specific enolase and synaptophysin. A diagnosis of paraganglioma was made. The lesion was excised completely and the patient did not develop recurrences or distant metastases after 8 months of follow-up. Paragangliomas arising in the nasal cavity and paranasal sinuses are extremely rare tumors. We report on the clinical, histopathological and immunohistochemical findings of our case and review the cases previously described in the literature.

[Tumors of the adrenal medulla and the paraganglia]

The sympathetic and parasympathetic paraganglia are the site of pheochromocytomas and paragangliomas. The adrenal pheochromocytoma and the abdominal paraganglioma derive from the sympathetic nervous system. The parasympathetic paragangliomas are predominantly localized in the head and neck region. Most pheochromocytomas are hormonally active and benign. The abdominal paragangliomas usually correspond to adrenal pheochromocytomas, but are more commonly malignant. The parasympathetic paragangliomas are usually benign, hormonally inactive and are most commonly located in the bifurcation of the carotid artery.

Immunohistochemical features of paragangliomas

Immunohistochemistry is part of the routine diagnosis of the neuroendocrine tumors. In our study, we included 52 paragangliomas with various localizations by routine histology and immunohistochemistry. In order to increase the diagnostic specificity, a complex immunohistochemistry panel has been performed consisting of Bcl-2, Ki-67, Bax and Pituitary Adenylate Cyclase-Activating Peptide (PACAP), somatostatin, VIP and Calcitonin Gene Related Peptide (CGRP). After heat induced antigen retrieval, the immunostaining was performed by StreptABC using DAB as a chromogen. We were the first to demonstrate the presence of Bax and PACAP in paragangliomas. Some of the used markers are of prognostic value. The relationship between Bcl-2 and Bax is decisive in generating the final response to the input apoptotic signals. The Ki-67 antigen staining has gained wide acceptance in prognostic evaluation of other tumor types. We noted a small number of Ki-67 positive cases, which signifies a low mitotic activity of these tumors and a relatively high number of Bax positivities (32.9%) and the much lower number of Bcl-2 positivities (11.39%), and could explain the benign behaviour of paragangliomas.

Simultaneously occurring liver metastases of pheochromocytoma and medullary thyroid carcinoma--a diagnostic pitfall with clinical implications for patients with multiple endocrine neoplasia type 2a

Malignant pheochromocytoma is an exceptional complication in patients with Multiple Endocrine Neoplasia Type 2a (MEN2a). In this paper, we report on a 53-year-old male patient with an evident RET gene germline mutation, who simultaneously developed hepatic metastases of medullary thyroid carcinoma (MTC) and pheochromocytoma. Comprehensive immunohistochemical investigations were performed to elaborate markers which could be useful for differentiating between MTC metastases and pheochromocytoma, respectively. Calcitonin and CEA, in particular cytokeratins and trefoil factor family 1 (TFF1), were detectable exclusively in MTC, whereas all the other markers revealed a comparable expression in both MTC and pheochromocytoma. The only clues that could indicate a potential malignant course were size, a lack of sustentacular cells and hyaline globules, and a focal spindle cell pattern in pheochromocytoma. Owing to a wide agreement in cellular differentiation and a lack of specific, routinely applicable markers for pheochromocytomas, a comprehensive and goal-directed immunohistochemistry is required to rule out pheochromocytoma metastasis in patients with MEN2a. A misinterpretation could lead to harmful clinical complications, as shown in the present case.

Proliferative index in phaeochromocytomas: does it predict the occurrence of metastases?

Evaluation of the malignant potential of phaeochromocytomas in the absence of metastases presents a formidable challenge to both clinicians and pathologists. Until now, no widely accepted clinical, histological, immunohistochemical or molecular method has become available to discriminate malignant from benign phaeochromocytomas. In other endocrine tumours, estimation of proliferative activity by MIB-1 immunostaining has emerged as a promising approach for the determination of metastatic potential. In this study, the utility of MIB-1 immunostaining as a predictive marker for the occurrence of metastases in phaeochromocytomas was evaluated. In addition, the density of S100-positive sustentacular cells was studied, since their depletion has been identified as a negative predictive marker in smaller series. Furthermore, several clinicopathological parameters were evaluated. One hundred and ten patients operated on for a total of 99 benign and 37 malignant phaeochromocytomas were studied. All malignant tumours had documented metastases. The histopathological diagnosis of primary tumours and metastases was reviewed and graded for angioinvasion, capsular extension, and intra-tumoural necrosis. The proliferative index (percentage of MIB-1-positive cells) and the density of S100-positive cells were assessed. In addition, age at resection, associated familial tumour syndromes, tumour size, and tumour location were recorded. Univariate analysis revealed statistically significant correlations between malignancy and proliferative index (p<0.0005) and depletion of S100-positive sustentacular cells (p<0.0005). Fifty per cent of the malignant, but none of the benign phaeochromocytomas had a proliferative index greater than 2.5%. Higher age at resection (p=0. 03), sporadic occurrence (p<0.0005), extra-adrenal location (p<0. 0005), tumour size (p<0.0005), and necrosis (p=0.03) were also significantly associated with malignancy. Logistic regression showed that proliferative index (p=0.0072), size (p=0.0022), and extra-adrenal location (p=0.0012) of the primary tumour were independently predictive for malignancy. In conclusion, this study indicates that assessing the proliferative activity of phaeochromocytomas by MIB-1 immunohistochemistry can predict the occurrence of metastases. The predictive value of S100 immunostaining, tumour size, and extra-adrenal location of the tumour was also confirmed.

Sustentacular cells in sporadic paraganglioma-like medullary thyroid carcinoma: report of a case with diagnostic and histogenetic considerations

Sustentacular cells (SCs) are glial supporting cells of the fetal, adult normal, and neoplastic extra and adrenal human chromaffin cell lineage. SCs have also been identified in some cases of medullary thyroid carcinoma (MTC), raising both diagnostic and histogenetic problems. We report a rare case of a sporadic paraganglioma-like variant of MTC showing numerous S-100 protein and glial fibrillar acid protein (GFAP) positive SCs encircling neoplastic cells in a nesting (Zellballen) pattern similar to that observed in paragangliomas or pheochromocytomas. Although stromal amyloid deposits were only focally detected, diagnosis was immunohistochemically confirmed by immunoreactivity of the neoplastic cells for cytokeratin, CEA, calcitonin, chromogranin A, neuron-specific-enolase, and synapthopysin. As for the histogenesis of SCs, if we assume that MTC is a neural crest-derived tumor, it is likely that these cells reflect the ability of the common precursor cell to differentiate towards a sustentacular-type glial cell lineage in addition to the typical neuroendocrine one. This viewpoint is supported by the evidence that rare cases of MTC may contain neoplastic or supporting cells showing a multidirectional differentiation (usually neuroendocrine and melanocytic) that recapitulates the different cell lineages arising from the developing neural crests.

Sustentacular cells in pulmonary neuroendocrine tumours

AIMS

To determine the prevalence of sustentacular cells across the range of pulmonary neuroendocrine tumours: typical and atypical carcinoid tumours and large cell and small cell neuroendocrine carcinomas.

METHODS AND RESULTS

Sustentacular cells were sought in 80 pulmonary neuroendocrine tumours by immunolabelling for S100 protein, nerve growth factor receptor and glial fibrillary acidic protein. Intratumoural macrophages and Langerhans cells were identified with the KP 1 (CD68) and CD1A antibodies. S100-positive sustentacular cells were present in 25 of 30 typical carcinoids, 200 of 25 atypical tumours, six of 10 large cell carcinomas and six of 15 small cell lesions. They were most numerous in the typical carcinoids but very few in the small cell carcinomas, their prevalance being clearly related to grade of differentiation and, in particular, to the degree of architectural organization.

CONCLUSIONS

Sustentacular cells are often found in pulmonary neuroendocrine tumours, especially better-differentiated lesions with a well-developed architecture. their prevalence clearly reflecting the degree of structural organization. Whether their prevalence is a useful prognostic indicator within a particular group of such tumours, such as the atypical carcinoids or the large cell carcinomas, as appears to be the case with paragangliomas, is unclear.

Diagnostic usefulness of sustentacular cells in paragangliomas: immunocytochemical and ultrastructural investigation

Neuroendocrine tumors may derive either from neuroectoderm or endoderm. Both may present with a similar histologic pattern known as "Zellballen" regardless of their histogenetic origin, making it difficult to separate the two different histogenetic entities in certain cases. To evaluate the usefulness of sustentacular cells in the recognition of tumors of paraganglionic origin, the authors analyzed immunohistochemical and ultrastructural characteristics of 25 paragangliomas and 19 pulmonary and 10 small intestinal carcinoids. Sustentacular cells with characteristic dendritic features, strong immunoreactivity for S-100 protein, and agranular cytoplasm by electron microscopy were found consistently in the paragangliomas and not found in typical carcinoid tumors, except for four examples of spindle cell carcinoid of the lung. The presence of sustentacular cells in tumors with "Zellballen" pattern therefore denotes paraganglionic origin.

Pulmonary clear cell carcinoid tumor: another entity in the differential diagnosis of pulmonary clear cell neoplasia

A clear cell variant of primary pulmonary carcinoid tumor is described. The tumor arose in a 53-year-old woman who was incidentally found to have a solitary pulmonary nodule in the left upper lobe during routine chest roentgenography. Histologically, the tumor was composed of predominantly clear to lightly eosinophilic, polygonal cells with bland nuclei arranged in sheets and nests. Nuclear pleomorphism, necrosis, vascular invasion, and mitotic figures were not seen. The tumor cells were negative for oil-red-O and periodic acid-Schiff stains with and without diastase pretreatment on frozen and formalin-fixed sections, respectively. During immunohistochemical evaluation, the tumor cells were focally positive for cytokeratin and diffusely positive for neuron-specific enolase and chromogranin. Electron microscopy performed on paraffin block-retrieved tissue showed the presence of electron-dense, neurosecretory-type granules and variably sized vacuolated areas within the cytoplasm. the nature of which remained unclear. Intracytoplasmic glycogen or lipid were not identified. To our knowledge, this is the first report of pulmonary clear cell carcinoid tumor.

Immunohistochemical identification and comparison of glial cell lineage in foetal, neonatal, adult and neoplastic human adrenal medulla

The differentiation of glial cells in developing, neonatal, adult and neoplastic human adrenal medulla has studied immunohistochemically. From 8 to 28 weeks' gestational age, S-100 protein and its beta-subunit revealed two different glial cell populations in adrenal glands, namely Schwann-like and sustentacular cells. Schwann-like cells were spindle-shaped cells forming a continuous layer around groups of sympathetic neuroblasts, often in contact with Schwann cells of nerve fibres entering neuroblastic groups. Sustentacular cells were round or oval cells with dendritic cytoplasmic processes; they were not associated with nerve fibres and mingled both with sympathetic neuroblasts and differentiating chromaffin cells. The developmental fate of Schwann-like cells was different from that of sustentacular cells. Schwann-like cells disappeared from the 28th week of gestational age, in association with the disappearance of sympathetic neuroblastic groups, and they were rarely found in neonatal and adult adrenal medulla. In contrast, sustentacular cells persisted between medullary chromaffin cells, and their number and dendritic cytoplasmic processes progressively increased from foetus to adult. In eight cases of primitive adrenal neuroblastic tumours of neonatal age (five undifferentiated neuroblastomas and three ganglioneuroblastomas), Schwann-like cells were found at the periphery of tumoral nests with a lobular growth pattern, while rare sustentacular cells were associated with neuroblasts. In two cases of adult phaeochromocytomas, only sustentacular cells were detected between chromaffin tumoral cells. Our findings suggest that the glial cell types and their distribution in primitive adrenal medulla tumours closely resemble those observed during development in the groups of adrenal sympathetic neuroblasts and in the clusters of chromaffin cells.

Paraganglioma: an unusual tumour of the parathyroid gland

A case of paraganglioma arising within a parathyroid gland is reported. The lesion was an incidental finding in a block dissection of neck performed for squamous carcinoma of the pharynx. A well-circumscribed lesion, exhibiting the characteristic pathological features of a paraganglioma, was embedded within the right inferior parathyroid gland. Due to its location, the chief histological differential diagnosis was an unusual variant of parathyroid adenoma. Immunohistochemistry and electron microscopy assisted in reaching a diagnosis. This, as far as we are aware, is the first reported case of a paraganglioma of the parathyroid gland.

Primary paraganglioma of the lung. Report of two cases and review of the literature

Two cases of primary paragangliomas of the lung are presented. The first occurred in a 69-year-old woman and was a grossly and histologically benign tumour. The other case occurred in a 33-year-old woman who had metastases to the peribronchial lymph nodes. This seems to be the second malignant case reported. No evidence of recurrence nor metastatic disease was found at follow-up, 8 months for the first case and 7 years for the second, respectively. The morphological and immunohistochemical findings are discussed and the literature comprising 20 cases is reviewed.

Olfactory neuroblastoma. An immunohistochemical, ultrastructural, and flow cytometric study

BACKGROUND

Olfactory neuroblastoma is an uncommon neuroectodermal tumor of the upper nasal cavity, microscopic features of which are not always homogeneous. No morphologic features have been found to correlate reliably with prognosis.

METHODS

Twenty-six olfactory neuroblastomas occurring in 14 females and 12 males, ages 18-78 years, were studied by immunohistochemistry, electron microscopy, and DNA flow cytometry. Survival rates were statistically analyzed relative to several variables.

RESULTS

Microscopically, 22 tumors formed a morphologic spectrum intermediate between paraganglioma (PG) and neuroblastoma (NB). Others included two ganglioneuroblastomas (GNB), one lesion exhibited biphasic (neuronal and epithelial) differentiation, and one tumor showed predominantly epithelial features. Immunoreactivity for neuronal and neuroendocrine markers included synaptophysin in 77%, neurofilament protein in 38%, class III beta-tubulin in 81%, and chromogranin A in 77%. In 88% of cases, elongated S-100 protein-positive cells surrounded tumor lobules. Cytokeratin and epithelial membrane antigen immunoreactivity were noted in six (23%) and two (8%) tumors, respectively. Aberrant p53 expression was detected in 16 tumors (62%). The Ki-67 labeling index (LI) varied from 0%-43.8% (mean, 7.4%). Ultrastructurally, 80-230 nm dense core granules were noted within perikarya and as in microtubule-containing processes in all of the 11 tumors studied by electromicroscopy. Lobules of seven tumors were surrounded by electron-dense sustentacular cells. Epithelial tumors exhibited obviously epithelial features in addition to neuronal differentiation. DNA flow cytometry demonstrated a high incidence of polyploidy and aneuploidy (78%) and a wide range of percent S phase fractions (1.5%-21.8%; mean, 9.0%). The study showed that longer survival rates are related significantly to (1) the occurrence of metastases which was linked to tumor subtype, (2) to a higher incidence of S-100 protein-positive cells, and (3) to a low (< 10%) Ki-67 labeling index.

CONCLUSIONS

The present study indicates that (1) although typical olfactory neuroblastomas exhibit PG/NB differentiation, they more closely resemble PG, (2) occasional tumors show GNB and/or epithelial differentiation, and (3) survival rates may correlate with S-100 protein immunoreactivity and Ki-67 LI. Cancer 1995; 76:4-19.

The biology and pathology of selected skull base tumors

This paper describes the pathobiology of some of the more common skull base tumors. In addition to clinicopathologic features, emphasis is placed upon methods of diagnosis utilizing immunoperoxidase stains and molecular markers that may or may not impact upon prognosis.

Mediastinal paragangliomas. A clinicopathologic and immunohistochemical study of 16 cases

BACKGROUND

Paragangliomas of the mediastinum are rare neoplasms. Because of their rarity, the spectrum of morphologic and immunohistochemical features and biologic behavior of these tumors in this location has not been delineated.

METHODS

A retrospective study of 16 cases of mediastinal paragangliomas was undertaken to evaluate their clinicopathologic and immunohistochemical features.

RESULTS

The patients were 10 men and 6 women whose ages ranged from 16-69 years of age (mean, 42.5 years). Twelve tumors were located in the posterior mediastinum, and three tumors were located in the anterior mediastinum. In one case, the exact location of the tumor within the mediastinum was not available. Microscopically, the nesting pattern (zellballen) was the most commonly encountered. Areas of stromal hyalinization were also frequent and were marked in two tumors. In two cases there was a prominent spindle cell component, and two cases showed granular cell changes in the cytoplasm of the tumor cells. Cellular pleomorphism was observed in the majority of cases. Occasional mitoses were seen in a few cases. Immunohistochemical studies in 10 cases showed chromogranin reactivity in 10 of 10 cases, S-100 protein in 9 of 10 cases, leu-enkephalin in 6 of 10 cases, and neurofilament protein in 5 of 10 cases. Keratin was negative in all cases studied. All patients underwent surgical resection of their tumors, and one patient underwent adjuvant radiation therapy. Follow-up information ranging from 1-168 months (mean, 84.5 months) was obtained in 12 patients. Nine patients (75%) were alive and well at last follow-up. In one patient the tumor metastasized to spinal space and bone marrow, and another patient died with metastases to lymph node, lung, and pelvis 14 years after initial diagnosis.

CONCLUSIONS

The only parameter found to correlate with aggressive behavior was the extent of circumscription and/or local infiltration of the tumor at initial resection. No clinical, histologic, or immunohistochemical features were otherwise found to separate aggressive from indolent clinical behavior. Regular follow-up is recommended in these patients due to the potential for these tumors to metastasize.

Frozen section diagnosis in a jugulo-tympanic paraganglioma

The light microscopy and immunohistochemical findings of a jugulo-tympanic paraganglioma occurring in a 29-year-old man are reported. Diagnostic difficulties from frozen sections are stressed and selected literature is briefly commented upon.

Tracheal paraganglioma

The trachea is an unusual site for paragangliomas, only four cases having been documented previously. A fifth case is presented here, together with immunohistochemical evidence that the tumour is biologically benign.