Primary sellar melanocytoma: pathological, clinical and treatment review.

BACKGROUND: Sellar melanocytomas represent a small subgroup of primary melanocytic tumors. They arise from melanocytes located in the meningeal lining of the sellar floor or in the diaphragma sellae and this location is very uncommon. Usually, sellar melanocytomas are benign and slow-growing tumors with a high likelihood of recurrence. PURPOSE: To our knowledge, due to the rarity of this condition, there are no guidelines regarding their diagnosis and treatment in the medical literature to date. We have developed a narrative review, analyzing the available studies regarding primary sellar melanocytomas reported in the medical literature. We have found ten papers on this topic and all of them are case reports. In all patients, tumor diagnosis was performed after the occurrence of neurological symptoms, in particular progressive visual loss or endocrinological disorders. The diagnosis is difficult, and it requires several preoperative and postoperative investigations, but histological examination is crucial. CONCLUSIONS: Transsphenoidal surgery is the first-choice treatment. In case of tumor's recurrence or regrowth, the role of radiation therapy and chemotherapy is not entirely clear.

Palate perforation differentiates cocaine-induced midline destructive lesions from granulomatosis with polyangiitis.

Cocaine abuse occasionally causes extensive destruction of the osteocartilaginous structures of the nose, sinuses and palate, which mimics the clinical picture of other diseases associated with necrotising midfacial lesions. The differentiation of cocaine-induced midline destructive lesions (CIMDL) and limited granulomatosis with polyangiitis (GPA) may be difficult, particularly if patients do not readily admit substance abuse. We studied 10 patients with CIMDL and palate perforation referred to our Unit between 2002 and 2015. All cases underwent nasal endoscopy, sinus CT or MRI and ANCA test. In 8 patients, a nasal biopsy was performed. The PubMed database was searched to review all cases of palate perforation described in patients affected by CIMDL or GPA. All 10 cases presented with septal perforation and inferior turbinate destruction. We found hard palate perforation in 7 patients, soft palate perforation in 2 patients, and perforation of both in one patient. ANCA testing was negative in 8 patients and positive in 2, with C-ANCA and P-ANCA specificity, respectively. A review of the English literature identified palate perforation in 5 patients with GPA and in 73 patients with CIMDL. The presence of palate perforation in patients with MDL may represent a clinical marker that strongly favors CIMDL over GPA.

The GIP/GIPR axis is functionally linked to GH-secretion increase in a significant proportion of gsp- somatotropinomas.

OBJECTIVE: Glucose-dependent insulinotropic polypeptide receptor (GIPR) overexpression has been recently described in a proportion of gsp- somatotropinomas and suggested to be associated with the paradoxical increase of GH (GH-PI) during an oral glucose load. DESIGN AND METHODS: This study was aimed at linking the GIP/GIPR pathway to GH secretion in 25 somatotropinomas-derived primary cultures and correlating molecular with clinical features in acromegalic patients. Given the impairment of the GIP/GIPR axis in acromegaly, an additional aim was to assess the effect of GH/IGF-1 stimulation on GIP expression in the enteroendocrine cell line STC-1. RESULTS: Nearly 80% of GIPR-expressing somatotropinomas, all of them negative for gsp mutations, show increased GH secretion upon GIP stimulation, higher sensitivity to Forskolin but not to somatostatin analogs. Besides increased frequency of GH-PI, GIPR overexpression does not appear to affect acromegalic patients' clinical features. In STC-1 cells transfected with GIP promoter-driven luciferase vector, IGF-1 but not GH induced dose-dependent increase in luciferase activity. CONCLUSIONS: We demonstrate that GIPR mediates the GH-PI in a significant proportion of gsp- acromegalic patients. In these cases, the stimulatory effect of IGF-1 on GIP promoter support the hypothesis of a functional GH/IGF-1/GIP axis. Further studies based on larger cohorts and the development of a stable transgenic model with inducible GIPR overexpression targeted to pituitary somatotroph lineage will be mandatory to establish the real role of GIPR in the pathogenesis of somatotropinomas.

Review of cerebellopontine angle medulloblastoma.

Cerebellopontine angle (CPA) medulloblastomas (MB) are rare lesions with few cases previously described in the literature. We report two further cases of CPA MB. The patients were a 22-year-old man and a 26-year-old woman with a mass developing in the CPA. The preoperative radiological diagnosis was vestibular schwannoma in the first case and petrosal meningioma in the second case. The patients were operated on through a retrosigmoid approach. The intraoperative findings revealed an intra-axial tumour and the histological diagnosis was classic type of MB in both cases. We review the literature and discuss pathological and radiological features and possible pathogenesis of CPA MB, underlining the necessity to consider MB in the differential diagnosis of CPA lesions.

The glucose-dependent insulinotropic polypeptide receptor is overexpressed amongst GNAS1 mutation-negative somatotropinomas and drives growth hormone (GH)-promoter activity in GH3 cells.

Somatic mutations in the GNAS1 gene, encoding the α-subunit of the heterotrimeric stimulatory G protein (Gαs), occur in approximately 40% of growth hormone (GH)-secreting pituitary tumours. By altering the adenylate cyclase-cAMP-protein kinase A pathway, they unequivocally give somatotroph cells a growth advantage. Hence, the pathogenesis of somatotropinomas could be linked to anomalies in receptors coupled to the cAMP second-messenger cascade. Among them, the glucose-dependent insulinotropic polypeptide receptor (GIPR) is already known to play a primary role in the impaired cAMP-dependent cortisol secretion in patients affected by food-dependent Cushing's syndrome. In the present study, 43 somatotropinomas and 12 normal pituitary glands were investigated for GIPR expression by quantitative reverse transcriptase-polymerase chain reaction, western blotting and immunohistochemistry. Tumoural specimens were also evaluated for GNAS1 mutational status. The effect of GIPR overexpression on cAMP levels and GH transcription was evaluated in an in vitro model of somatotropinomas, the GH-secreting pituitary cell line GH3. GIPR was expressed at higher levels compared to normal pituitaries in 13 GNAS1 mutation-negative somatotropinomas. GIP stimulated adenylyl cyclase and GH-promoter activity in GIPR-transfected GH3 cells, confirming a correct coupling of GIPR to Gαs. In a proportion of acromegalic patients, GIPR overexpression appeared to be associated with a paradoxical increase in GH after an oral glucose tolerance test. Whether GIPR overexpression in acromegalic patients may be associated with this paradoxical response or more generally involved in the pathogenesis of acromegaly, as suggested by the mutually exclusive high GIPR levels and GNAS1 mutations, remains an open question.

Evolution of a prolactin-secreting pituitary microadenoma into a fatal carcinoma: a case report.

Pituitary carcinomas are very rare tumors, nearly always presenting as widely invasive masses, although the hallmark of these lesions is the finding of distant metastases. One third of reported cases are prolactin (PRL)-secreting tumors. We report the case of a fatal pituitary carcinoma evolving within 4 years from a PRL-secreting microadenoma. A 22-year-old woman presented because of galactorrhea. Evaluation of the patient disclosed slight hyperprolactinemia and magnetic resonance imaging (MRI) showed a 7-mm intrapituitary lesion, which responded to treatment with cabergoline. About 4 years after the first evaluation she developed sudden headache, ptosis, and diplopia in the right eye. MRI disclosed the growth of a large pituitary mass, invading the right cavernous sinus. Despite two trans-sphenoidal surgical procedures followed by gamma-knife radiosurgery, the patient showed rapid local progression of the tumor and the occurrence of new lung lesions, probably of metastatic nature. The patient died 7 months after the development of her first neurological symptoms because of tumor apoplexy and subsequent subarachnoid hemorrhage. This case represents the first documented rapid evolution from a microprolactinoma initially responding to dopamine agonists to a fatal pituitary carcinoma.

Reactive perivascular T-cell infiltrate predicts survival in primary central nervous system B-cell lymphomas.

Well-established histopathological prognostic factors are lacking in primary central nervous system (CNS) lymphomas (PCNSL). The present study investigated the presence and prognostic role of tumour necrosis (TN) and reactive perivascular T-cell infiltrate (RPVI), defined as a rim of small reactive T-lymphocytes occurring alone or located between the vascular wall and large neoplastic cells, in tumour samples from 100 immunocompetent patients with PCNSL. World Health Organization histotypes of the patients were: 96 diffuse large B-cell lymphomas, two Burkitt-like lymphomas, one anaplastic large T-cell lymphoma and one unclassified B-cell lymphoma. TN was observed in 24 (24%) cases and RPVI in 26 (36%) of 73 assessable cases. Patients with RPVI-positive lesions exhibited a significantly better overall survival (OS) than patients with RPVI-negative lymphoma, particularly among patients treated with high-dose methotrexate-based chemotherapy (3-year OS: 59 +/- 14% vs. 42 +/- 9%, P = 0.02). By contrast, the presence of TN did not demonstrate prognostic significance. Multivariate analysis confirmed an independent association between RPVI and survival. In conclusion, the presence of RPVI is independently associated with survival in PCNSL. This parameter can be easily and routinely assessed at diagnosis on histopathological specimens.

Intrasellar paraganglioma: a case report and review of the literature.

Intrasellar paragangliomas are very rare lesions with only six previous cases described in the literature. We present a further case of intrasellar paraganglioma. The patient was a 52 yr-old man who developed two transient ischemic attacks. A CT scan showed an intra- and supra-sellar expanding lesion, which was regarded as a possible non-functioning pituitary macro-adenoma. Removal of the lesion was accomplished by transsphenoidal surgery. Histological examination was diagnostic of a paraganglioma. We review the literature and discuss pathological features and possible pathogenesis of sellar and parasellar paragangliomas, underlining the necessity to consider paraganglioma in the differential diagnosis of sellar lesions.

Neuromelanin and iron in human locus coeruleus and substantia nigra during aging: consequences for neuronal vulnerability.

In this study a comparative analysis of iron molecules during aging was performed in locus coeruleus (LC) and substantia nigra (SN), known targets of Parkinson's Disease (PD) and related disorders. LC and SN neurons, especially the SN pars compacta, degenerate in PD and other forms of parkinsonism. Iron and its major molecular forms, such as ferritin and neuromelanin (NM), were measured in LC and SN of normal subjects at various ages. Iron levels were lower, H-ferritin/iron ratio was higher and the iron content in NM was lower in LC than in SN. Iron deposits were abundant in SN tissue, very scarse in LC tissue and completely absent in pigmented neurons of both SN and LC. In both regions H- and L-ferritins were present only in glia. This suggests that in LC neurons iron mobilization and toxicity is lower than that in SN and is efficiently buffered by NM. Ferritins accomplish the same buffering function in glial cells.

Correlation between clinical characteristics and proliferative activity in patients with craniopharyngioma.

OBJECTIVES: The aim of the study was to correlate the Ki-67 and cyclin A labelling index (LI) with clinical characteristics and risk of recurrence of craniopharyngiomas. METHODS: 47 consecutive patients were studied, 21 female and 26 male, aged 34.3 (2.8) years. Immunohistochemical analysis was performed on paraffin wax embedded material using monoclonal antibodies directed against the proliferation associated nuclear antigen Ki-67 and cyclin A. RESULTS: The median Ki-67 LI was 8.6% (interquartile range, 4.4%-14.0%). Ki-67 LI was significantly higher in tumours with a heavy inflammatory reaction and diabetes insipidus at presentation, whereas other clinical and histological features were not associated with the proliferation index. There was a strong linear correlation between Ki-67 LI and cyclin A LI (r = 0.77; p<0.0001); therefore, cyclin A LI showed the same clinical and histological relations described for Ki-67 LI. Recurrence of craniopharyngioma occurred in 13 of 46 patients (28.3%). The median Ki-67 LI in the 13 recurrent craniopharyngiomas (9.0%) was not significantly different from that of non-recurring tumours (7.9%). Cyclin A LI was also not associated with the risk of relapse. CONCLUSIONS: This study confirms the great variability of proliferative activity in craniopharyngiomas. Ki-67 and cyclin A LIs were associated with the presence of a heavy inflammatory reaction and diabetes insipidus, but did not correlate with the long term risk of tumour regrowth.

Primary brain CD30+ ALK1+ anaplastic large cell lymphoma ('ALKoma'): the first case with a combination of 'not common' variants.

BACKGROUND: Primary central nervous system lymphomas (PCNSLs) are rare tumors, mostly represented by diffuse large B cells. PCNSLs with a T phenotype are less frequently reported; even rarer are anaplastic large cell lymphomas (ALCLs). PCNSL ALCLs are commonly represented, like their systemic counterpart, by a variably prevalent amount of large pleomorphic tumor cells ('hallmark cells'), and this feature enhances their recognition. Patient and methods We report the first case of primary brain CD30+ ALK-1+ ALCL with a T-cell phenotype, showing the combination of both the 'lymphohistiocytic' and the 'small cell' variants of the disease. A few elements consistent with 'hallmark cells' were recognizable. However, these cells were never prominent, increasing diagnostic difficulties. Immunohistochemistry results were critical for the correct interpretation. Our findings also differ from the majority of PCNSL ALCLs for the absence of tumor necrosis and the lack of prominent mitotic activity. The neuroimaging picture was not specific. A comparison with literature data concerning the clinical/instrumental features shows a very frequent meningeal involvement in PCNSL ALCLs, in contrast to the majority of PCNSLs. CONCLUSION: The occurrence of such a rare form of ALCL may widen the spectrum of differential diagnoses in PCNSL and their recognition may allow a rapid diagnosis, thus encouraging adequate treatment, which should take into account the high rate of meningeal involvement observed in these cases.

Effects of octreotide treatment on the proliferation and apoptotic index of GH-secreting pituitary adenomas.

To investigate the effects of octreotide administration on the growth rate of GH-secreting pituitary adenomas, we measured both the Ki-67 labeling index (LI) and the apoptotic index in tumor specimens from octreotide-treated or matched untreated acromegalic patients. Thirty-nine patients who received octreotide until the day of or the day before surgery and 39 untreated patients matched for sex, age, tumor size, extension, and invasiveness were studied. Immunocytochemical analysis was performed on paraffin-embedded material using a monoclonal antibody (MIB-1) directed against a proliferation-associated nuclear antigen, Ki-67, to measure the growth fraction. Apoptosis was assessed by the terminal deoxynucleotidyl transferase-mediated deoxy-UTP nick endlabeling method, using a monoclonal antibody recognizing areas of DNA fragmentation. The Ki-67 LI and apoptosis were counted on separate slides in at least 1000 evaluable cells. Octreotide-treated patients showed a lower Ki-67 LI (1.8 +/- 0.3%) than untreated controls (3.8 +/- 0.7%; P < 0.02). Overall, the mean Ki-67 LI of treated patients was 53% lower than that in untreated patients. The antiproliferative effect of octreotide occurred independently of tumor extension and invasiveness. Octreotide-treated and untreated patients showed similar apoptotic indexes (0.6 +/- 0.2% and 0.8 +/- 0.3%, respectively). There was a positive correlation between the Ki-67 LI and the apoptotic index (r = 0.29; P < 0.03). Our study demonstrates that acromegalic patients receiving chronic octreotide treatment have a lower value of the proliferation marker Ki-67, but no significant difference in the apoptotic index compared with matched untreated patients. The antiproliferative effect of octreotide on GH-secreting adenomas should imply a lower risk of tumor growth during long-term chronic treatment with the drug.

Primary angiitis of the central nervous system: serial MRI of brain and spinal cord.

MRI findings in primary angiitis of the central nervous system (PACNS) are highly variable, ranging from normal to diffusely abnormal. We describe brain and spinal cord abnormalities in patients with PACNS and changes over time, to provide criteria which could be useful for differential diagnosis. We reviewed six patients, with a final diagnosis of PACNS, who underwent serial contrast-enhanced brain and spinal MRI. Follow-up ranged from 12 to 60 months. Brain MRI showed multiple small abnormalities in all patients, giving high signal on T2-weighted images, focal or diffuse, mainly in deep and subcortical white matter; four patients had both supra- and infratentorial lesions. On the initial MRI, in five patients, almost 90% of the abnormal foci showed contrast enhancement. Virchow-Robin perivascular spaces were enlarged and simultaneously enhancing in four patients. Three patients also had spinal cord abnormalities, in the cervical and thoracic segments in two, and exclusively cervical segment in one. Two patients had brain biopsy-proven PACNS; in the remainder, the diagnosis of PACNS was presumptive, considering similarities in clinical and MRI features and MRI follow-up. On MRI, after steroid and immunosuppressive therapy, a significant decrease in the number and size of the abnormalities, enhancing and nonenhancing and of enhancing perivascular spaces was observed. Simultaneous enhancement of brain and spinal cord lesions and of perivascular spaces, at the onset of the disease, which resolves during follow-up, can therefore suggest PACNS.

Irradiation fields and doses in glioblastoma multiforme: are current standards adequate?

AIMS AND BACKGROUND: The optimum conventional radiotherapy in glioblastoma multiforme patients has not been clearly defined by prospective trials. To better characterize a standard radiotherapy in glioblastoma multiforme, the impact on survival of different fields and doses was analyzed in a retrospective single center series. METHODS: One hundred and forty-seven patients with glioblastoma multiforme, submitted to biopsy only (n = 15), subtotal (n = 48) or total resection (n = 82) and who completed the planned postsurgical radiotherapy, were considered. The median age was 57 years, the male/female ratio 1.5/1, and the performance status > or =70 in 76%. Whole brain irradiation, followed by a boost to partial brain, was used in 75 cases with a whole brain dose of 44-50 Gy (median, 46) and a partial brain dose of 56-70 Gy (median, 60 Gy). Partial brain irradiation alone was used in 72 patients with a dose of 56-70 Gy (median, 61 Gy). Ninety-eight patients received 56-60 Gy (median, 59 Gy) to partial brain whereas 49 patients received 61-70 Gy (median, 63 Gy). RESULTS: There was an almost significantly longer survival in patients irradiated to the partial brain alone with respect to those also receiving whole brain radiotherapy (P = 0.056). Doses >60 Gy significantly prolonged survival (P = 0.006). Multivariate analysis confirmed that the impact on survival of radiation dose was independent of age, performance status, extent of surgery, field of irradiation and the use of chemotherapy. The extent of irradiation field was not independently related to improved survival. CONCLUSIONS: Our retrospective findings suggest that we reflect on the adequacy of the current standard irradiation parameters. Well-designed prospective trials are necessary to standardize the radiotherapy control group in patients with glioblastoma multiforme to be compared in phase III trials with innovative therapeutic approaches.

Combined treatment with high-dose methotrexate, vincristine and procarbazine, without intrathecal chemotherapy, followed by consolidation radiotherapy for primary central nervous system lymphoma in immunocompetent patients.

OBJECTIVES: To assess the feasibility and the activity, as well as the efficacy to treat meninges, of chemotherapy (CHT) containing high-dose methotrexate (HD-MTX) followed by radiation therapy (RT), without intrathecal CHT, in patients with primary central nervous system lymphoma. METHODS: Eligibility criteria were histologically proven diagnosis, disease limited to the CNS, age < or = 70, ECOG performance status < or = 3, HIV-negative and no prior treatment. Thirteen patients (1996-1999; median age 54 years) received two courses of vincristine 1.4 mg/m2 day 1, MTX 3 g/m2 days 3 and 10 and procarbazine 100 mg/m2 days 1-14 every 4 weeks. Patients who achieved a complete remission were referred to RT, those with progressive disease were excluded from further study; all the remaining patients received a third course of CHT followed by RT. RESULTS: Twelve patients responded to CHT (overall response rate = 92%, complete response rate = 77%): 9 underwent consolidation RT, 3 did not. Two patients experienced severe acute toxicity; lethal pulmonary thromboembolism and transient renal failure. Five patients relapsed: 2 after CHT and 3 after RT. Relapse was local in all cases, with a case of concomitant hepatic involvement. No cases of ocular or meningeal relapse were observed. In contrast to high-dose cytarabine-containing CHT, salvage therapy with temozolomide produced good results. Two patients died of treatment-related neurotoxicity. Six patients are alive with a median follow-up of 17 months, and a 2-year overall survival (OS) of 61%. The median survival of the 9 patients who completed the planned treatment is 25+ months with a 2-year OS of 80%. CONCLUSIONS: HD-MTX, procarbazine and vincristine followed by RT, without intrathecal therapy, produce similar results with respect to other HD-MTX-containing regimens. These results seem to suggest that adequate meningeal treatment is possible without intrathecal drug delivery, even in CSF-positive patients. Corroborating data from a larger series are, however, necessary. Temozolomide should be tested in relapsed patients in a phase II prospective trial.

Spinal cord involvement in primary angiitis of the central nervous system: a report of two cases.

SUMMARY: We report two patients with suspected primary angiitis of the CNS who underwent serial contrast-enhanced MR imaging of the spinal cord. MR abnormalities were multiple and enhancing, and located within the cervical and thoracic cord. Brain MR findings and brain biopsy specimens were positive for primary angiitis of the CNS. On follow-up MR studies, obtained after steroid and immunosuppressive therapy, a significant decrease in the number and size of the enhancing and nonenhancing abnormalities was observed, along with clinical improvement. Numerous small and enhancing abnormalities with a primarily posterior location, seen at the onset of the disease and resolved on follow-up studies, may be considered suggestive of a diagnosis of primary angiitis of the CNS.

Glial cyst of the pineal gland: case report and considerations about surgical management.

Symptomatic glial cyst of the pineal gland are rare lesions. Origin, natural history and factors leading to cyst enlargement are not completely clear; thus management remain uncertain in some cases. We report a case of symptomatic glial cyst and analyze the implication for surgery. Surgical management is indicated in patients presenting hydrocephalus, mass effect or symptoms related to mesencephalic dysfunction. The infratentorial supracerebellar approach represent the first choice for this condition allowing easy orientation with wide exposure of the tumor and good visibility of deep venous systems that may be preserved. Size of the tumor is a key element in evaluation of the treatment and the appropriate course for asymptomatic cyst less than 1 cm in size consist of conservative management. Periodic follow up is always indicated.

Proliferation index of nonfunctioning pituitary adenomas: correlations with clinical characteristics and long-term follow-up results.

OBJECTIVE: The recurrence of nonfunctioning pituitary adenomas (NFPAs) after surgical removal is common. The aim of our study was to investigate and correlate the growth fraction of NFPAs with clinical characteristics and long-term follow-up results. METHODS: Tumor specimens were obtained from 101 consecutive patients with NFPAs (48 female patients and 53 male patients; mean age, 52.0 +/- 1.5 yr). Specimens were immediately fixed in 10% buffered formalin and then embedded in paraffin. The Ki-67 antigen was assessed by immunocytochemical analysis using the monoclonal antibody MIB-1. The Ki-67 antigen labeling index (LI) was determined by counting a total of at least 1,000 neoplastic nuclei. RESULTS: The mean Ki-67 LI for the 101 patients was 2.4 +/- 0.3% (range, 0-23.0%). Only age at surgery was inversely correlated with the Ki-67 LI; sex, maximal tumor diameter, and invasiveness into the cavernous sinuses did not significantly affect the Ki-67 LI. The mean follow-up period was 39.7 +/- 2.1 months. During follow-up monitoring, 23 patients experienced tumor recurrence, after a mean period of 28.6 +/- 4.8 months. Invasiveness of the tumor on preoperative magnetic resonance imaging scans was the strongest predictor of late tumor recurrence, followed by previous pituitary surgery, younger age, and lack of postoperative radiotherapy. The Ki-67 LI had no independent prognostic value. CONCLUSION: Our study suggests that the clinical characteristics of patients with NFPAs, except for age at surgery, are not correlated with the Ki-67 LI. Moreover, the Ki-67 LI does not seem to provide independent information to identify patients at high risk for tumor recurrence.

Acromegaly associated with a granular cell tumor of the neurohypophysis: a clinical and histological study. Case report.

Acromegaly is usually caused by a growth hormone (GH)-secreting pituitary adenoma, and hypersecretion of GH-releasing hormone (GHRH) from a hypothalamic or neuroendocrine tumor accounts for other cases. The authors report on the unusual association of acromegaly with a granular cell tumor of the neurohypophysis. A 42-year-old woman with a 10-year history of acral enlargement, headache, and menstrual abnormalities was referred to our department for a suspected GH-secreting pituitary adenoma. The patient's basal GH levels were mildly elevated at 4.8 microg/L, were not suppressed in response to an oral glucose tolerance test, and increased paradoxically after administration of thyrotropin-releasing hormone. The patient's insulin-like growth factor-1 (IGF-1) level was elevated at 462 microg/L, whereas a magnetic resonance image of the sella turcica revealed an intra- and suprasellar lesion that was compatible with a diagnosis of pituitary adenoma. A transsphenoidal approach to remove the lesion, which was mainly suprasellar, was successful during a second operative attempt, resulting in the clinical and biochemical regression of the patient's acromegaly. Four months postoperatively, the patient's basal GH level was 0.9 microg/L and her IGF-1 level was 140 microg/L. Histological analysis of the operative specimen demonstrated a granular cell tumor of the neurohypophysis, which when stained proved negative for pituitary hormones and GHRH. This case represents the first reported association between a granular cell tumor of the neurohypophysis and acromegaly. Granular cell tumor of the neurohypophysis could be added to the restricted list of neoplastic causes of acromegaly secondary to hypersecretion of a GH-releasing substance.

Determination of the proliferation and apoptotic index in adrenocorticotropin-secreting pituitary tumors : comparison between micro- and macroadenomas.

We investigated the growth fraction and cell loss fraction in a large group of patients with Cushing's disease subdivided according to tumor size. Fifty-one patients, 8 males and 43 females, aged 12 through 61 years (mean age 34.6 +/- 1.5 years), were studied. Thirty-six patients had a microadenoma and the remaining 15 a macroadenoma. Immunohistochemical analysis was performed on paraffin-embedded material using a monoclonal antibody (MIB-1) directed against a proliferation-associated nuclear antigen, Ki-67, to measure the growth fraction. Apoptosis was assessed by the terminal deoxynucleotidyl transferase-mediated dUTP nick end labeling method, using a monoclonal antibody recognizing areas of DNA fragmentation. Ki-67 labeling index and apoptosis were counted on separate slides in at least 1000 evaluable cells. Patients with a macroadenoma had a significantly higher value of Ki-67 index (9.3 +/- 2.7%) than patients with microadenoma (2.8 +/- 0.5%; P < 0.002), whereas the apoptotic index was not significantly different in the two groups (1.7 +/- 0.8% in macroadenomas versus 0.8 +/- 0.3% in microadenomas). Our study shows that ACTH-secreting macroadenomas are characterized by a higher cell growth fraction than microadenomas, whereas the cell loss fraction is not different. A high proliferation rate seems to play a major role in determining the progression from small to large pituitary tumors in Cushing's disease.