Histopathology, cytology and cytochemistry of pheochromocytomas and paragangliomas including chemodectomas

Aggressive Malignant Paraganglioma Involving the Pancreas and Vertebral Column

Paraganglioma (PGL) is a rare neuroendocrine tumor arising from chromaffin cells outside the adrenal medulla. The most common sites are the abdomen and head and neck. Seventy percent (70%) of PGLs are sporadic, and 30% are hereditary; the latter are more often aggressive and malignant and occur in young adults. We report a case of a 36-year-old woman with a history of hypertension and abdominal pheochromocytoma resected at the age of 10 years who presented with back pain. Magnetic resonance imaging of the spine showed vertebral metastasis at L2-L5. Computed tomography of the abdomen showed a mass in the body of the pancreas and a laparoscopic biopsy was performed. The tumor cells had granular eosinophilic/basophilic cytoplasm and showed a nested pattern (Zellballen) with a prominent vascular network and infiltration of dense fibrous connective tissue. Strong and diffuse expression of synaptophysin in tumor cells, S100 expression in sustentacular cells at the periphery of nests, and lack of pancytokeratin expression supported the diagnosis of PGL. Due to limited tissue, it was difficult to determine metastatic vs primary neoplasm of the pancreas. The earlier age of onset and history of abdominal pheochromocytoma suggested the possibility of hereditary PGL associated with succinate dehydrogenase (SDH) deficiency. The tumor cells lacked SDHB expression. Germline mutation testing for SDH was recommended. The patient underwent palliative radiotherapy and systemic chemotherapy. Most PGLs are benign and asymptomatic, but there is an increased risk of cardiovascular mortality secondary to catecholamine secretion, and surgical excision is curative. Malignant PGLs are rare (10-40%), have poor prognosis, and are incurable. Increased size of the tumor, deep tissue infiltration, and high proliferative index increase the risk of malignancy, but metastasis is required for the diagnosis of malignant PGL. The advanced disease is treated with surgical removal of the tumor and combined radiotherapy and chemotherapy.

The genomic origins of the Bronze Age Tarim Basin mummies

The identity of the earliest inhabitants of Xinjiang, in the heart of Inner Asia, and the languages that they spoke have long been debated and remain contentious¹. Here we present genomic data from 5 individuals dating to around 3000-2800 BC from the Dzungarian Basin and 13 individuals dating to around 2100-1700 BC from the Tarim Basin, representing the earliest yet discovered human remains from North and South Xinjiang, respectively. We find that the Early Bronze Age Dzungarian individuals exhibit a predominantly Afanasievo ancestry with an additional local contribution, and the Early-Middle Bronze Age Tarim individuals contain only a local ancestry. The Tarim individuals from the site of Xiaohe further exhibit strong evidence of milk proteins in their dental calculus, indicating a reliance on dairy pastoralism at the site since its founding. Our results do not support previous hypotheses for the origin of the Tarim mummies, who were argued to be Proto-Tocharian-speaking pastoralists descended from the Afanasievo^1,2 or to have originated among the Bactria-Margiana Archaeological Complex³ or Inner Asian Mountain Corridor cultures⁴. Instead, although Tocharian may have been plausibly introduced to the Dzungarian Basin by Afanasievo migrants during the Early Bronze Age, we find that the earliest Tarim Basin cultures appear to have arisen from a genetically isolated local population that adopted neighbouring pastoralist and agriculturalist practices, which allowed them to settle and thrive along the shifting riverine oases of the Taklamakan Desert.

Divergent role of (68)Ga-labeled somatostatin analogs in the workup of patients with NETs: AIIMS experience

Neuroendocrine tumors (NETs) encompass a wide range of rare and heterogeneous neoplasms arising from the neural crest. Diagnosis of NETs is conventionally done by a combination of common clinical symptoms and biochemical evidence of hormonal excess, which these tumors are known to secrete. After a diagnosis of NET is established, a search for its localization is carried out using common morphologic imaging methods such as ultrasonography, computed tomography (CT), and magnetic resonance imaging (MRI). The main problem with structural imaging is, however, its inability to distinguish between endocrine and exocrine lesions. Functional imaging of NETs started with use of iodine-131-meta-iodobenzylguanidine ((131)I-MIBG) and has come a long way since. From accurate demonstration of functioning tumors to detection of small and occult lesions, functional imaging has penetrated almost every aspect of NET management. Procedures such as (131/123)I-MIBG, (111)In-Octreoscan and others are rapidly giving way to use of PET/CT based on the superior resolution of the system and the availability of target-specific positron-emitting radiotracers. The availability of (68)Ga from generator-based radionuclide systems, namely (68)Ge/(68)Ga generators, opened up a new era of molecular imaging for NETs. A multitude of somatostatin analogs can be easily radioliganded with (68)Ga using heterocyclic macromolecular bifunctional chelating systems for targeted diagnosis of somatostatin receptor-expressing tumors, used most effectively to date for detection of NETs. This chapter focuses on our experience at the All India Institute of Medical Sciences, New Delhi regarding the divergent roles of (68)Ga-labeled somatostatin analogs in the workup of patients with NETs.

Metastatic paraganglioma of the spine: case report and review of the literature

Paragangliomas are relatively rare tumors, accounting for only about 0.3% of all neoplasms. Most paragangliomas are defined as benign in nature, but 10-20% possess metastatic potential. There have been scattered reports of metastatic paraganglioma in the literature, but in rare circumstances, paragangliomas can metastasize to the spinal column causing destruction or compression of the spinal cord, clinically manifesting as pain or neurological deficit. We report a case of metastatic paraganglioma in which a 47-year-old man had spinal metastasis from a primary abdominal paraganglioma and was found to be positive for SDHB mutation, portraying negative implications for prognosis. Long-term follow-up is reported. In addition, we review the literature on the topic of metastatic paraganglioma, management of paragangliomas involving spine, and touch on the importance of the presence of SDHB mutations in these cases.

Prospective evaluation of ⁶⁸Ga-DOTA-NOC PET-CT in phaeochromocytoma and paraganglioma: preliminary results from a single centre study

OBJECTIVE

To evaluate the role of (68)Ga-labelled [1, 4, 7, 10-tetraazacyclododecane-1, 4, 7, 10-tetraacetic acid]-1-NaI(3)-Octreotide ((68)Ga-DOTA-NOC) whole body positron emission tomography-computed tomography (PET-CT) as a functional imaging approach for phaeochromocytoma and paraganglioma.

METHODS

Thirty-five unrelated patients (Median age-34.4 years; range: 15-71) were evaluated in this prospective study. PET-CT was performed after injection of 132-222 MBq of (68)Ga-DOTA-NOC. Images were evaluated by two experienced nuclear medicine physicians both qualitatively as well as quantitatively (standardised uptake value-SUVmax). In addition we compared the findings with (131)I Metaiodobenzylguanidine (MIBG) scintigraphy, which was available for 25 patients. Histopathology and/or conventional imaging with biochemical markers were taken as the reference standard.

RESULTS

44 lesions were detected on (68)Ga-DOTA-NOC PET-CT imaging with an additional detection of 12 lesions not previously known, leading to a change in management of 6 patients. Sensitivity, specificity and accuracy were 100%, 85.7%, and 97.1% on a per patient basis and 100%, 85.7% and 98% on per lesion basis, respectively.(131)I MIBG scintigraphy was concordant with (68)Ga-DOTA-NOC PET-CT in 16 patients and false negative in 9 patients.

CONCLUSION

(68)Ga-DOTA-NOC PET-CT is highly sensitive and specific for the detection of phaeochromoctyomas and paragangliomas. It seems better than (131)I MIBG scintigraphy for this purpose.

KEY POINTS

• ( 68 ) Ga-DOTA-NOC PET-CT seems useful in patients with phaeochromocytoma and paraganglioma. • This prospective single centre study showed that it has high diagnostic accuracy. • (68) Ga-DOTA-NOC PET-CT seems superior to (131) I-MIBG in these patients.

Studies for estimating the biologic behavior and prognosis of paragangliomas in the head and neck

Despite a large number of histopathologic and immunohistochemical studies, the biologic behavior and prognosis of paragangliomas (glomus tumors) of the head and neck still remain uncertain. In the present study 36 specimens from 32 patients who underwent surgery for a paraganglioma were examined. The examinations included routine histology, quantitative DNA analysis based on image cytometry, immunohistochemical detection of the proliferating cell nuclear antigen (PCNA) along with visualization of nucleolar organizer regions (AgNOR). According to LeCompte, the paragangliomas were histologically divided into three subcategories: 16 patients had a paragangliomatous tumor. 14 patients had an adenomatous tumor, and 6 patients had an angiomatous tumor. Quantitative DNA analysis revealed three categories of tumors with characteristical DNA pattern; DNA type I tumors were pure diploid, DNA type II tumors had stemlines at 2c and 4c and were therefore recognized as diploid-tetraploid. Aneuploid cells were not apparent in these two groups. DNA type III tumors had stemline ploidies exceeding 2c and 4c. Aneuploid cells were present in all of these tumors. The biologic behavior of these lesions therefore must be recognized as suspicious. DNA type III tumors and adenomatous tumors showed the highest values for the PCNA scores, indicating a higher proliferation rate and a more rapid growth pattern in these lesions. Twenty patients could be followed over a period of up to 110 months. Five of these patients developed a recurrent tumor. All of them had DNA type III tumors. The DNA indices showed significantly higher values in the recurrent tumor group. The 2c deviation index (DI) and the entropy value had the highest prognostic significance. No correlation to clinical follow-up was found for the AgNOR score. Based on these results, prognostic indices for paragangliomas were developed: patients with a tumor having a 2c DI exceeding 2.0, entropy value of more than 4.0. 5c exceeding rate more than 8.0, and a PCNA score more than 20.0% can be recognized as being at high-risk for developing recurrent disease.

Prognostic Factors Including Proliferation Markers Ki-67, bax, and bcl-2 in Temporal Bone Paraganglioma

Valuable criteria with which to predict the clinical behavior of the temporal bone paraganglioma or the response to treatment are lacking. The analysis of markers of cell proliferation is a possibility to estimate the prognosis. Extensive patient data on 40 temporal bone paragangliomas were gathered over the years and correlated with the data obtained by staining histologic sections with bcl-2, bax, and MIB I markers of cellular proliferation. The immunohistochemistry was in all cases negative for bcl-2, positive for bax, and for Ki-67 positive in 20% of tumors. The scores for Ki-67 did not correlate with the majority of clinical parameters, except for treatment modality, preoperative hearing loss, and cranial nerve involvement. The tendency toward poorer hearing and a higher incidence of preoperative lower cranial nerve palsies was demonstrated in patients with higher Ki-67 scores. Furthermore, the higher rate of subtotal tumor removals in these patients reveals technical difficulties in accomplishing a radical removal, although the incidence of residual tumors was thus not affected. In view of the present information obtained with proliferation markers, the site of tumor origin still remains the most predictive variable for the course of the disease.

Treatment of malignant pheochromocytoma

Pheochromocytoma (PCC) is a rare disease, mainly sporadic, but also associated with some familial disorders, with a malignancy frequency of approximately 10%. Only the presence of distant metastases, derived from large pleomorphic chromaffin cells, is widely accepted as a criterion of malignancy. Variable symptoms may be caused by production and release of catecholamines. Since there is no curative treatment for malignant PCC and due to its unfavorable prognosis, assuring quality of life is one of the main therapeutic objectives. Besides a long-term medical treatment of symptoms using selective alpha-1 blockers and nonselective, noncompetitive alpha- and/or beta-blockers, debulking surgery is the first treatment step. In case of a sufficient uptake of (123)I-MIBG treatment with targeted radiation therapy, use of (131)I-MIBG is an option as an adjuvant therapy, following debulking surgery. Chemotherapy should be applied to patients without positive MIBG-scan, with no response to (131)I-MIBG or progression after radionuclide treatment, and especially in cases with high proliferation index. The most effective chemotherapy regimen appears to be the CVD-scheme, including cyclophosphamide, vincristine, and dacarbazine. The so-called targeted molecular therapies with treatment combinations of temozolomide and thalidomide, or sunitinib monotherapy, and novel therapeutic somatostatin analogues have shown promising results and should thus encourage clinical trials to improve the prognosis of metastatic PCC. Within this review the current treatment modalities and novel molecular strategies in the management of this disease are discussed and a treatment algorithm is suggested.

Neuroendocrine neoplasms of the larynx: Advances in identification, understanding, and management

While 85-90% of laryngeal malignancies prove to be squamous carcinomas, the second most common tumour type found in the laryngeal region will prove to be a member of the family of neuroendocrine tumours. Laryngeal carcinoid tumours have a capacity for metastasis, and so are more aggressive tumours than their light microscopic features might imply--5-year survival rates are in the vicinity of 50%. Laryngeal atypical carcinoid tumours are lesions with a well-recognized capacity for local recurrence as well as metastasis, with a 5-year survival of just under 50%. Laryngeal small cell neuroendocrine carcinomas are particularly aggressive tumours, with a 5-year survival of no more than 5-10%. Laryngeal paragangliomas are lesions without any real capacity for metastasizing. Surgical excision is the mainstay of treatment of carcinoid tumours, atypical carcinoid tumours, and paragangliomas. Small cell neuroendocrine carcinomas are chiefly treated by way of radiation and chemotherapy; the role of adjuvant therapy in the treatment of atypical carcinoid tumours remains to be established.

Cervical Paraganglioma Mimicking a Parathyroid Adenoma on Tc-99m Sestamibi Scintigraphy

A 32-year-old man with a clinical and biochemical profile suggestive of primary hyperparathyroidism presented with a soft tissue mass on the left side of the neck. Multiphasic planar and SPECT Tc-99m sestamibi (MIBI) scintigraphy showed focally increased tracer concentration in the mass. Subsequent histopathology and immunostaining identified the mass as a parathyroid hormone-secreting cervical paraganglioma, indicating that this tumor should be considered in the differential interpretation of MIBI concentration in the neck.

Sclerosing Paraganglioma

Nineteen cases of a distinctive variant of paraganglioma characterized by extensive collagen deposition resulting in a pattern of growth that resembled an invasive malignant neoplasm are described. The patients were 3 men and 16 women, 32 to 69 years of age (mean, 50.5 years). The tumors were located in the carotid body region, parapharyngeal region, and mediastinum. Tumor size ranged from 2 to 6 cm in greatest diameter. Grossly, the tumors were described as rubbery to firm, tan-red, and with extensive areas of sclerosis. Histologic examination showed nests and cords of tumor cells separated by broad bands of fibrous tissue. The tumor cells ranged from round to polygonal with abundant cytoplasm to elongated spindle cells with scant cytoplasm. Nuclear cytomegaly was present focally enhancing the atypical appearance of the tumor cell population in 17 cases. Mitoses were sparse (<1 x 10 HPF), and there was no evidence of necrosis in any of the cases. Foci of vascular and perineural invasion were present in 2 and 4 cases, respectively. The most striking morphologic feature was the presence of irregular cords and bands of hyalinized fibrous tissue that compartmentalized the lesion into irregular nests, islands, or cords of tumor cells, imparting them with an infiltrative appearance. All the tumors showed positive immunostaining for chromogranin, synaptophysin, and monoclonal neuron specific enolase. S-100 protein stains identified a sustentacular cell network, whereas cytokeratin AE1/AE3 was negative in all cases. Clinical follow-up in 14 cases, ranging from 2 months to 20 years (mean follow-up, 6.6 years) showed evidence of local recurrence in 2 cases and the development of a separate tumor in the contralateral neck in 1 case. The remainder of patients were free of recurrence or metastasis following simple local excision. Because of the prominent sclerosis, a diagnosis of an invasive malignant neoplasm was initially considered in the majority of cases. Sclerosing paraganglioma should be included in the differential diagnosis of sclerosing lesions of the head and neck region and mediastinum. Appropriate immunohistochemical stains may be of aid for establishing the correct diagnosis.

Imaging of pheochromocytoma and paraganglioma

Paragangliomas are tumours that arise within the sympathetic nervous system originating from the neural crest. These tumours can be found anywhere from the neck to the pelvis in locations of sympathetic ganglions. Although in the majority of paragangliomas the diagnosis is based on measuring catecholamines and metabolites in plasma or urine, imaging plays an important preoperative role. Today, there are several morphological and radionuclide imaging methods available that predict tumour localisation and tumour extent and give anatomic information to the surgeon. MRI is the morphological imaging modality of choice in localising pheochromocytomas and extra-adrenal paragangliomas. It provides excellent anatomic detail and has the advantage of lacking ionising radiation. The overall accuracy of computed tomography (CT) in detecting primary adrenal pheochromocytomas is very high, but CT lacks in specificity as difficulties may occur in distinguishing between paragangliomas and other tumour entities. The major advantages of radionuclide imaging are very high specificity and routinely performed whole-body scanning. Furthermore, metabolic imaging is not influenced by artifacts like scar tissue or metallic clips in post-surgical follow-up. Currently, a reported specificity of 99% and a cumulative sensitivity of about 90% in paragangliomas make (123)I-MIBG the most important nuclear imaging method. However, (18)F-DOPA-PET seems to be a very promising procedure which offers higher accuracy. The higher spatial resolution of PET-scanners enables the detection of small lesions not visualised with (123)I-MIBG. Both use of radiolabelled somatostatin analogue like (111)In-pentetreotide and (18)F-FDG is limited due to low specificity of the tracers and should be restricted to MIBG- and F-DOPA-negative cases.

The clinically inapparent adrenal mass: update in diagnosis and management

Clinically inapparent adrenal masses are incidentally detected after imaging studies conducted for reasons other than the evaluation of the adrenal glands. They have frequently been referred to as adrenal incidentalomas. In preparation for a National Institutes of Health State-of-the-Science Conference on this topic, extensive literature research, including Medline, BIOSIS, and Embase between 1966 and July 2002, as well as references of published metaanalyses and selected review articles identified more than 5400 citations. Based on 699 articles that were retrieved for further examination, we provide a comprehensive update of the diagnostic and therapeutic approaches focusing on endocrine and radiological features as well as surgical options. In addition, we present recent developments in the discovery of tumor markers, endocrine testing for subclinical disease including autonomous glucocorticoid hypersecretion and silent pheochromocytoma, novel imaging techniques, and minimally invasive surgery. Based on the statements of the conference, the available literature, and ongoing studies, our aim is to provide practical recommendations for the management of this common entity and to highlight areas for future studies and research.

18F-DOPA positron emission tomography for the detection of glomus tumours

The purpose of this study was to evaluate (18)F-DOPA whole-body positron emission tomography ((18)F-DOPA PET) as a biochemical imaging approach for the detection of glomus tumours. (18)F-DOPA PET and magnetic resonance imaging (MRI) were performed in ten consecutive patients with proven mutations of the succinate dehydrogenase subunit D ( SDHD) gene predisposing to the development of glomus tumours and other paragangliomas. (18)F-DOPA PET and MRI were performed according to standard protocols. Both methods were assessed under blinded conditions by two experienced specialists in nuclear medicine (PET) and diagnostic radiology (MRI). Afterwards the results were compared. A total of 15 lesions (four solitary and four multifocal tumours, the latter including 11 lesions) were detected by (18)F-DOPA PET. Under blinded conditions, (18)F-DOPA PET and MRI revealed full agreement in seven patients, partial agreement in two and complete disagreement in one. Eleven of the 15 presumed tumours diagnosed by (18)F-DOPA PET were confirmed by MRI. The correlation of (18)F-DOPA PET and MRI confirmed three further lesions previously only detected by PET. All of them were smaller than 1 cm and had the signal characteristics of lymph nodes. For one small lesion diagnosed by PET, no morphological MRI correlate could be found even retrospectively. No tumour was detected by MRI that was negative on (18)F-DOPA PET. All tumours diagnosed by MRI showed a hyperintense signal on T2-weighted images and a distinct enhancement of contrast medium on T1-weighted images. The mean tumour size was 1.5+/-0.5 cm. (18)F-DOPA PET seems to be a highly sensitive metabolic imaging procedure for the detection of glomus tumours and may have potential as a screening method for glomus tumours in patients with SDHD gene mutations.

Paragangliomas of the head and neck: clinical, morphological and immunohistochemical aspects

CONTEXT

Protein marker positivity can assist in the definition of the therapeutic approach towards head and neck paragangliomas. The establishment of the therapeutic approach should incorporate the results of such an investigation.

OBJECTIVE

To establish criteria for benignity and malignancy of vagal and jugular-tympanic paragangliomas, via the study of the relationships of sex, age, tumor size, duration of complaints, site, family history, presence of metastases, treatment, histological architecture and cell type with the immunohistochemical reactions to S100 protein, chromogranin and AgKi67.

DESIGN

A retrospective study of histological and clinical records.

SETTING

The Heliópolis and Oswaldo Cruz tertiary general hospitals, São Paulo.

SAMPLE

8 cases of head and neck paragangliomas.

MAIN MEASUREMENTS

Determination of degree of positivity to paragangliomas via immunohistochemical reactions.

RESULTS

1). The protein markers for the principal cells (AgKi67 and chromogranin) were sensitive in 100% of the tumors when used together. 2). S100 protein was well identified in the cytoplasm and nucleus of sustentacular cells and underwent reduction in the neoplasias.

CONCLUSIONS

Chromogranin was proven to be a generic marker for neuroendocrine tumors; S100 protein was positive in all 8 cases and the AgKi67 had low positivity in all cases.

Biologic characteristics of paragangliomas of the nasal cavity and paranasal sinuses

Paragangliomas of the nasal cavity and paranasal sinuses are extremely rare. This study was conducted to investigate the biologic characteristics of these lesions on different molecular levels and to estimate their biologic behavior. Operative specimens of three patients who underwent surgery for a paraganglioma of the nasal cavity (one case) or paranasal sinuses (two cases) were investigated by routine histology, quantitative DNA analysis, and immunohistochemical assessment of proliferation markers (i.e., Proliferating Cell Nuclear Antigen, PCNA; Ki67-MIB-1), the expression of cell-surface antigens, which reflect the tumor-stroma interaction (i.e., CD 44 v0.4/5 and 6, CD 54, CD 106), oncogene products (nm-23; p53), and bcl-2 as a marker of apoptosis. Histologically, two tumors were paragangliomas of the adenomatous subtype, one lesion was classified as angiomatous. According to DNA analysis, aneuploid cells were detected in all tumors. Two of three paragangliomas were classified as a DNA type III pattern, implying a high percentage of aneuploid cells and an aggressive behavior. Immunohistochemically, paragangliomas of the nasal cavity showed increased scores for both proliferation markers tested, indicating a rapid growth pattern. According to the expression of cell-surface markers and oncogene products, these tumors displayed an aggressive behavior and an infiltrating growth pattern. The highest value for the parameters of quantitative DNA analysis and highest proliferation scores were found in a tumor of a patient who developed multiple tumor recurrences after radical excision of the lesion with clear margins, and finally died of disease. In conclusion, paragangliomas of the nasal cavity and paranasal sinuses examined in this study should be regarded as suspicious concerning their biologic and clinical behavior. Radical excision, and in cases with highly aggressive biology, postoperative radiation therapy are recommended. Tumor biologic examinations can help to recognize high-risk patients for developing recurrences and possibly lesions with a malignant behavior and to enhance our understanding of the biology of these extremely rare tumors of the nasal cavity and paranasal sinuses.

Primary ependymoma of the mediastinum: a clinicopathologic study of three cases

Primary mediastinal ependymomas are unusual tumors, with only two case reports previously reported in the literature. In this study, we review our experience with three cases of primary mediastinal ependymomas, including the clinical, histopathologic, immunohistochemical, and ultrastructural features. The three patients in this study were white women with a mean age of 50 years (age range, 36 to 71 years). Presenting symptoms were nonspecific; radiographically, all lesions were circumscribed posterior mediastinal masses without evidence of bone involvement. There was no evidence of central nervous system, sacral, or pelvic ependymoma. All tumors were completely resected, ranged in size from 5 to 7 cm (mean, 6 cm), and exhibited glistening pseudocapsules. Two tumors had a solid, tan-gray cut surface and one lesion was cystic with a mural tumor nodule. All neoplasms showed histologic features of conventional cellular ependymomas with perivascular pseudorosettes and occasional true ependymal rosettes. Germ cell components were not present in any case and immunohistochemical analysis showed glial fibrillary acidic protein, S-100, and patchy cytokeratin immunoreactivity in all three cases as well as absence of reactivity for HMB 45, chromogranin, and synaptophysin. Ultrastructural features included multipart "zipper-like" junctions, intracytoplasmic lumina containing microvilli, occasional cytoplasmic basal bodies, and apical cilia. A microscopic metastasis was present in a regional lymph node in one case at the time of resection; however, there is no evidence of recurrence or distant metastasis in any of the cases during the postoperative period (mean length of follow-up, 64 months). Ependymomas rarely occur in the mediastinum and have a predilection for the posterior mediastinum. The paravertebral location, microscopic identification of adjacent sympathetic ganglia, and lack of teratomatous or other germ cell components suggest that mediastinal ependymomas are likely derived from paravertebral ependymal rests. Primary mediastinal ependymomas are characterized by a prolonged and indolent clinical course. Metastasis to regional lymph nodes may occur, but distant metastases are unusual in our experience. Complete surgical excision seems to offer the best chance for long-term survival.

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.

Gangliocytic paraganglioma of the duodenum: report of a case with immunocytochemical and ultrastructural investigation

A case of gangliocytic paraganglioma is reported in a 70-year-old female presenting as a polypoid tumor of the second portion of the duodenum. Immunohistochemical and ultrastructural features of the tumor indicate that gangliocytic paraganglioma of the duodenum (GPD) represents an unique tumor originating from the neuroectodermal derivative exhibiting dual phenotypic expression toward paraganglionic and epithelial (neuroendocrine) cells. These findings correlate well with the literature and it is further suggested that GPD belongs to the histopathologic spectrum of tumors derived from the neural crest. The findings offer a plausible explanation for histogenetic possibilities of the occurrence of pure epithelial tumors (i.e., carcinoid-like tumors) in the paraganglionic systems. The patient remains with no evidence of disease 4 years following a simple polypectomy.

Malignant pheochromocytoma of the anterior mediastinum: PET findings with [18F]FDG and 82Rb

A case of a malignant pheochromocytoma arising from the anterior mediastinum is presented. We report the use of positron emission tomography with 82Rb and [18F]fluorodeoxyglucose to successfully image this neoplasm.

Atypical lung carcinoid with GFAP immunoreactive cells

A case of atypical carcinoid with peculiar histological and ultrastructural pattern and immunohistochemical phenotype is presented. The neoplasm is composed of three types of cells. Type 1 cells are small to medium sized, fusiform, with scarce cytoplasm and are arranged in fascicles. Type 2 cells are cuboidal and line acinar structures. Type 3 cells have more abundant eosinophilic cytoplasm, larger nuclei and are arranged in fascicles intersecting with fascicles of type 1 cells, and sometimes surround acinar structures. The three cell types are present both in the primary lesion and in its lymph node metastases. Immunohistochemistry demonstrates immunoreactivity of all cell types for general neuroendocrine markers. Cytokeratin immunoreactivity is more prominent in type 1 and 2 cells, and is only focally expressed in type 3 cells. Type 3 cells are also immunoreactive for glial fibrillary acidic protein (GFAP), alpha-actin, S-100 protein, vimentin. Electron microscopic examination confirms the neuroendocrine nature of the cells, and show that type 3 cells have prominent bundles of intermediate filaments, electron-dense granules and junctional complexes. To our knowledge, this is the first case of atypical lung carcinoid with GFAP immunoreactivity. The nature of type 3 GFAP positive cells is unclear. There are some clues pointing to their sustentacular nature, and other ones pointing to a myoepithelial origin, but the data are inconclusive. Type 3 cells may be the malignant counterpart of sustentacular cells seen in typical carcinoids, but their GFAP positivity and the presence of electron-dense granules are very unique features, which differentiates them from sustentacular cells. Alternatively, their unusual GFAP + immunohistochemical phenotype may be due to aberrant expression of cytoskeletal proteins.

Reliability of criteria for ultrastructural identification of neuroendocrine granules

For full diagnostic use to be made of the neurosecretory granule, the range of sizes, forms, and staining qualities for this cytoplasmic organelle, along with the extent of its expression in various neoplasms, must be established. Neurosecretory type granules occasionally occur in nonneuroendocrine tumors. A series of carcinoids of the lung provides a model for assessing the morphologic types of cytoplasmic granules identified by antibodies to chromogranin A and immunogold labeling. The results show that granule structure in tumors is pleomorphic. Despite having sizes within the expected range, many labeled and, indeed, unlabeled secretory granules are atypical, particularly in structural form. Cell-to-cell variation in the proportion of even typical neurosecretory granules labeling for chromogranin A is the rule. Studies correlating biochemical, immunohistochemical, electron microscopic, and perhaps in situ hybridization characteristics are required to define better the criteria for unequivocal identification of neurosecretory granules in tumors.

Cushing syndrome-associated pheochromocytoma and adrenal carcinoma. An immunohistological investigation

Seven adrenal carcinomas and seventeen pheochromocytomas (PHs), two of which were clinically associated with a Cushing's syndrome and one associated with multiple endocrine neoplasia Type II (MEN-II), were investigated immunohistologically with a panel of antibodies against intermediate filament proteins, a proliferation-associated nuclear antigen (Ki-67), neuroendocrine tumor markers, and different hormones on paraffin-embedded tissue sections and, from 19 cases, also on frozen tissue sections. Synaptophysin proved to be the most reliable tumor cell marker on both snap-frozen and paraffin-embedded tissue but, like antibodies against NSE, yielded unspecific stainings in the carcinomas. The two Cushing-associated pheochromocytomas (CaPH) showed the same immunohistological profile as the other PHs, except one chromogranin-negative tumor. Five PHs showed weak reactivity for calcitonin, one for serotonin, and two for a-HCG in small amounts. All PHs lacked other hormone expression, including ACTH. The average growth fraction was small (2.2%) in 13 cases, but 80% of the tumor cells were proliferating in one case of CaPH. Adrenal carcinomas showed only weak or no expression of keratin in one case, a homogenous or droplet, non-filamentous cytoplasmic staining with antibodies against neurofilament in frozen tissue section, and they were completely chromogranin-negative. The average growth fraction was 7.6% in 5 cases.

Extra-adrenal pheochromocytoma

Extra-adrenal pheochromocytomas may arise in any portion of the paraganglion system, although they most commonly occur below the diaphragm. The most common site of occurrence of extra-adrenal pheochromocytoma is the superior para-aortic region between the diaphragm and lower renal poles. Although the traditional teaching has been that 10% of all pheochromocytomas are at extra-adrenal sites, this may be an underestimation. Extra-adrenal pheochromocytomas probably represent at least 15% of adult and 30% of childhood pheochromocytomas. They may be malignant in up to 40% of the cases, although conflicting data add to the uncertainty of this point. Patients with tumors arising at extra-adrenal sites commonly present with headache, palpitations, sweating and hypertension. The diagnosis is most often confirmed by demonstrating increased catecholamine production, usually by measurement of urinary catecholamines and/or their metabolites. CT scanning is presently the imaging procedure of choice for localization. The roles of MRI and 131I-MIBG scintigraphy in the localization process are still being determined. Thorough preoperative pharmacological preparation, attentive intraoperative monitoring and aggressive surgical therapy all have an important role in achieving the safest and most successful outcome. Complete surgical excision is the treatment of choice for primary extra-adrenal pheochromocytoma as well as recurrent or metastatic disease. When residual tumor cannot be resected, medical therapy for symptomatic relief is preferred, since radiotherapy and chemotherapy have limited effectiveness. Extra-adrenal pheochromocytomas are more likely to recur and to metastasize than their adrenal counterparts, making lifelong followup with annual determinations of catecholamine production essential.

Cystic neuroendocrine retroperitoneal carcinoma

Retroperitoneal tumors are rare. Most of these tumors arise from mesothelial or connective tissues in the retroperitoneum. We report the first case, for us, of a cystic neuroendocrine retroperitoneal carcinoma in a 71-year-old woman. The discussion is focused on the radiographic findings, immunohistochemical studies and the controversial diagnosis.

Pheochromocytoma

The cytoplasmic granules in an adrenal pheochromocytoma were predominantly ovoid with loose-fitting limiting membranes and eccentrically positioned dense cores. The occurrence of similar granules in a recurrent tumor involving the organ of Zuckerkandl in a second patient suggests that the latter tumor should be designated an extraadrenal pheochromocytoma.

Aorticopulmonary paraganglioma (aortic body tumor): report of a case

A case of aorticopulmonary paraganglioma in a 57-year-old man is described. The tumor comprised nests of uniform cells in a fibrovascular stroma. Electron microscopy revealed abundant neurosecretory granules, and S-100 protein staining demonstrated scattered sustentacular cells at the periphery of typical zellballen. The findings in this case correlated with those of studies on the prognosis for extraadrenal paragangliomas.

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

Surgical specimens of 65 adrenal and 27 extra-adrenal paragangliomas, the latter comprising 11 carotid body, five jugulotympanic, one aorticopulmonary, eight aorticosympathetic and two visceral autonomic tumours, were examined immunocytochemically for the presence of glial fibrillary acid protein (GFAP) and S-100 protein. Six adrenal and four extra-adrenal (one parasympathetic and three sympathetic) neoplasms pursued a malignant clinical course. S-100 staining of sustentacular (type 2) cells was seen in both adrenal (48/65) and extra-adrenal (23/27) lesions, the 10 malignant tumours being entirely devoid of S-100 protein positive cells. GFAP positivity of type 2 cells was seen in only 16 of the extra-adrenal tumours, all of these lesions belonging to the group of benign parasympathetic paragangliomas. The presence of S-100 positive type 2 cells may thus help to exclude malignancy in individual paraganglioma cases, while GFAP positivity of such cells renders possible the correct typing of benign parasympathetic paragangliomas.

Augmented enkephalin-immunoreactivity in adrenaline-producing phaeochromocytomas

Immunohistochemical studies for methionine- and leucine-enkephalin were performed on 26 phaeochromocytomas to elucidate the patho-physiological roles of enkephalins. Positive reactions were seen in all phaeochromocytomas with varying intensities. The location of methionine- and leucine-enkephalin agreed fairly well with each other. Stronger immunostaining was obtained in phaeochromocytomas secreting both adrenalin and noradrenaline than in those secreting predominantly noradrenaline. Paroxysmal hypertension was frequently observed in patients with adrenalin-secreting phaeochromocytomas, especially those with marked enkephalin positivity. Urinary excretion of metanephrine was significantly correlated with enkephalin positivity. These findings show that all phaeochromocytomas retain the ability to produce enkephalins of the adreno-medullary or extra-medullary chromaffin tissues from which they derive. Augmented enkephalin-immunoreactivity in adrenalin-producing phaeochromocytomas may be interpreted as reflecting a close association of enkephalins with adrenalin under physiological conditions.

Non-functional malignant paraganglioma of the stomach

We report the second case of a malignant paraganglioma of the stomach in a 56-year-old female patient. However, our case is the first investigated by immunohistochemistry and electron-microscopy. The tumour was characterized immunohistochemically by the presence of neurofilament protein, glial fibrillary acidic protein, S-100 protein, neuron-specific enolase, chromogranin A, ACTH, leu-enkephalin and vasoactive intestinal polypeptide, and ultrastructurally by demonstration of neurosecretory granules and paranuclear intermediate filament whorls. Despite massive metastatic spread in the abdominal cavity, the patient is still alive 4 years after initial diagnosis.

Bronchial carcinoids with S-100 positive sustentacular cells. A comparative study with gastrointestinal carcinoids, pheochromocytomas and paragangliomas

Fourty-six bronchial carcinoids, twelve tumourlets and twenty areas of neuroendocrine cell dysplasia (NED) were immunohistochemically evaluated for various neuroendocrine markers, S-100 protein (S-100), myelin basic protein, intermediate filaments, actin, Leu-7 and several neurohormonal polypeptides. Eighteen of the bronchial carcinoids (39.1%) showed a biphasic cell pattern, with abundant stellate-shaped S-100 positive cells (SC). SC were not reactive for chromogranin A, myelin basic protein, cytokeratins, neurofilaments, glial fibrillary acidic protein or actin, and were only occasionally weakly positive for vimentin. SC were not detected in the tumourlets nor in the NED observed. For comparison a group of other neuroendocrine tumours (11 gastrointestinal carcinoids, 4 pheochromocytomas and 4 paragangliomas) were immunostained for S-100, chromogranin A and actin. SC similar to the ones detected in the bronchial carcinoids could be detected in appendiceal carcinoids, paragangliomas and in two out of four pheochromocytomas. Our present data are in keeping with a Schwannian/sustentacular nature of SC rather than that of a histiocytic or myoepithelial nature. We suggest that SC-rich bronchial carcinoids are biphasic tumours, which could be designed "paraganglioid" bronchial carcinoids. The relationship between SC-rich bronchial carcinoids and tumourlets/NED is a matter of further investigation: SC-rich bronchial carcinoids may either differentiate in a biphasic pattern during tumoural growth or may not be histogenetically related to tumourlets.

Endocrine cells producing regulatory peptides

Recent data on the immunolocalization of regulatory peptides and related propeptide sequences in endocrine cells and tumors of the gastrointestinal tract, pancreas, lung, thyroid, pituitary (ACTH and opioids), adrenals and paraganglia have been revised and discussed. Gastrin, xenopsin, cholecystokinin (CCK), somatostatin, motilin, secretin, GIP (gastric inhibitory polypeptide), neurotensin, glicentin/glucagon-37 and PYY (peptide tyrosine tyrosine) are the main products of gastrointestinal endocrine cells; glucagon, CRF (corticotropin releasing factor), somatostatin, PP (pancreatic polypeptide) and GRF (growth hormone releasing factor), in addition to insulin, are produced in pancreatic islet cells; bombesin-related peptides are the main markers of pulmonary endocrine cells; calcitonin and CGRP (calcitonin gene-related peptide) occur in thyroid and extrathyroid C cells; ACTH and endorphins in anterior and intermediate lobe pituitary cells, alpha-MSH and CLIP (corticotropin-like intermediate lobe peptide) in intermediate lobe cells; met- and leu-enkephalins and related peptides in adrenal medullary and paraganglionic cells as well as in some gut (enterochromaffin) cells; NPY (neuropeptide Y) in adrenaline-type adrenal medullary cells, etc.. Both tissue-appropriate and tissue-inappropriate regulatory peptides are produced by endocrine tumours, with inappropriate peptides mostly produced by malignant tumours.