Pituitary Adenoma with Neuronal Choristoma (PANCH): Composite Lesion or Lineage Infidelity?

Fifteen cases of the rare association of pituitary adenoma and neuronal choristoma (PANCH) were investigated by histology, immunohistochemistry, and electron microscopy. Acromegaly was apparent clinically in 11 patients and was equivocal in 1, and 3 lesions appeared to be nonfunctioning. Histology revealed various proportions of chromophobic PA and nervous tissue consisting of neuronlike cells and neuropil. Immunohistochemistry documented growth hormone (GH) in every PA, including those unassociated with clinical acromegaly. In contrast, the NCH component showed no consistent immunohis-tochemical profile. Most frequent reactivities were for the pituitary hormone a subunit, thyroid-stimulating hormone, and GH, whereas only a few cases displayed scattered positivity for GH-releasing hormone. Low-molecular weight keratin tested positive in PAs and in a few cells and processes of an NCH. A few fibrous bodies were immunoreactive for neurofilament protein. Electron microscopy revealed sparsely granulated GH cell adenoma, neurons, and neuropil. Cells intermediate between PA and neurons were numerous in 1 lesion. The present morphologic findings as well as lack of GH cell hyperplasia and the consistent association of NCH with but one type of PA do not support the causative role of NCH in the initiation of PA, as proposed previously. It appears that NCH is the result of neuronal differentiation within sparsely granulated GH cell adenomas.     

Pituitary Adenoma with Neuronal Choristoma (PANCH): Composite Lesion or Lineage Infidelity?

Fifteen cases of the rare association of pituitary adenoma and neuronal choristoma (PANCH) were investigated by histology, immunohistochemistry, and electron microscopy. Acromegaly was apparent clinically in 11 patients and was equivocal in 1, and 3 lesions appeared to be nonfunctioning. Histology revealed various proportions of chromophobic PA and nervous tissue consisting of neuronlike cells and neuropil. Immunohistochemistry documented growth hormone (GH) in every PA, including those unassociated with clinical acromegaly. In contrast, the NCH component showed no consistent immunohis-tochemical profile. Most frequent reactivities were for the pituitary hormone a subunit, thyroid-stimulating hormone, and GH, whereas only a few cases displayed scattered positivity for GH-releasing hormone. Low-molecular weight keratin tested positive in PAs and in a few cells and processes of an NCH. A few fibrous bodies were immunoreactive for neurofilament protein. Electron microscopy revealed sparsely granulated GH cell adenoma, neurons, and neuropil. Cells intermediate between PA and neurons were numerous in 1 lesion. The present morphologic findings as well as lack of GH cell hyperplasia and the consistent association of NCH with but one type of PA do not support the causative role of NCH in the initiation of PA, as proposed previously. It appears that NCH is the result of neuronal differentiation within sparsely granulated GH cell adenomas.     

Collision Tumors of the Sella: Craniopharyngioma and Silent Pituitary Adenoma Subtype 3: Case Report

Collision tumors of the sella turcica are rare and consist mainly of more than one type of pituitary adenoma, usually a corticotropin- and a prolactin-producing adenoma. The association of a craniopharyngioma and a pituitary adenoma is rare. Herein, we report the first case of an association between craniopharyngioma and silent pituitary adenoma subtype 3. It involved a 12-year-old boy who underwent a frontal craniotomy with surgical removal of a calcified sellar tumor. Histology revealed an adamantinomatous craniopharyngioma; however, by electron microscopy, there was conclusive evidence of adenoma cells showing the ultrastructural features of silent pituitary adenoma subtype 3. Endocrine and neuroimaging as well as detailed immunohistochemical and ultrastructural studies were undertaken. The literature is also reviewed.     

GH and PRL-producing pituitary adenoma with neuron-like differentiation

A pituitary adenoma with neuron-like differentiation in the sella turcica is reported. Sections of the tumor showed a mixture of adenoma cells, ganglionic cells, and neuropil-like structures by light microscopy. Both pituitary adenoma cells and large cells recognized as ganglionic cells by H&E were strongly immunoreactive for both growth hormone (GH) and prolactin (PRL), which indicated that these large cells had properties similar to those of pituitary adenoma cells. Furthermore, electron microscopy (EM) revealed characteristic low electron-dense secretory granules as well as GH-type large electron-dense secretory granules in adenoma cells, neuropils, and swollen bulbs of neuronal endings, which indicated that these three populations may be of the same origin. Furthermore, we could not find typical cell bodies of ganglionic cells by EM. These results are consistent with a hypothesis that attempts to explain the origin of the neuronal components by the neuronal differentiation of adenoma cells. Thus, the best designation of our tumor may be “pituitary adenoma with neuron-like differentiation.”     

Squamous metaplasia following necrosis of the adenohypophysis and of a chromophobe adenoma of the pituitary

Summary Two cases of pituitary necrosis are presented, one occurring post partum in an otherwise normal gland, the other in a large chromophobe adenoma. In both cases the necrotic tissue became surrounded by squamous epithelial nests that developed through metaplasia from glandular cells of the adenohypophysis and adenoma cells respectively. The squamous elements were seen 6 days after the clinical events leading to pituitary necrosis in the first case and 20 days after pituitary apoplexy (hemorrhagic necrosis of an adenoma) in the second case. In contradistinction to the commonly found squamous nests which are usually located in the pars tuberalis and presumably develop through a slower process, the changes in the present two cases indicate that squamous metaplasia can develop quite rapidly at the margins of a necrotic process of the pituitary, either deep in the gland as in case 1 or occupying the entire circumference of a necrotic tumor as in case 2.     

Adenocarcinoma arising in a traditional serrated adenoma of the rectosigmoid colon with osseous metaplasia

Within the gastrointestinal tract, osseous metaplasia is an extremely rare phenomenon. It has only recently been described within a traditional serrated adenoma. Serrated colorectal carcinoma is the end point of the serrated neoplasia pathway. Left sided lesions typically arise from traditional serrated adenomas and represent only 8% of colorectal carcinomas. Herein reported is a case of colorectal adenocarcinoma arising from a traditional serrated adenoma with the rare occurrence of osseous metaplasia within the adenoma. The significance of the finding is discussed.     

Concurrent tubulovillous adenoma and transitional cell carcinoma associated with diffuse gastric and intestinal metaplasia of the defunctioned ureter

Villous adenoma is a common lesion of the gastrointestinal tract, but it is rare in the ureter. Thus, as far as we know, only one case limited to this location has been described. Intestinal metaplasia of the urothelium is not rare. However, only one case of gastric metaplasia with pseudopyloric glands has been described in the literature. We here report in detail on a tubulovillous adenoma of the ureter associated with diffuse gastric and intestinal metaplasia and a concurrent primary, solid, high grade transitional cell carcinoma, with extensive clear cell change, in a 56-year-old male patient. He had undergone a left nephrectomy for renal tuberculosis twenty years earlier, and the lesions developed in the ureteric stump. To the best of our knowledge, such a combination of lesions has not been reported previously either in the ureter or in the rest of the urinary tract. The coexistence of diverse lesions in our case might represent the pluripotentiality of the urothelium in association with chronic inflammation and neoplastic induction. The present report also emphasizes the metaplastic and malignant potential of a defunctioned urothelial structure. This case is of particular interest, because these coexistent lesions arose simultaneously with an anatomically separate adenocarcinoma of the rectum (Dukes' B). The patient died 76 days after admission. The dismal prognosis of our case was determined by the advanced anatomical stage and the histological high grade of the transitional cell carcinoma of the ureter.     

The Pituitary in Gigantism

To compare the pituitary pathology of gigantism to that of acromegaly, 19 surgically resected lesions were studied from 10 males and 9 females, ages 13–49 (mean, 19 yr) with excessive height (≥95th percentile), onset of disease prior to puberty, elevated growth hormone (GH) levels despite glucose suppression, and a pathologically confirmed GH-producing pituitary mass. One patient had MEN-I. The lesions included 18 adenomas and 1 case of pure hyperplasia. The median, mean, and range of serum GH and prolactin (PRL) levels were 64, 235, 5–1000 ng/mL and 47, 146, 29–770 ng/mL, respectively. Of the 8 adenoma specimens accompanied by nontumoral pituitary (i.e., tissue wherein the presence of hyperplasia was assessable), 3 (37%) demonstrated both. Of the 18 tumors, 78% were macroadenomas and 22% were grossly invasive; their immunophenotypes included GH (5%), GH and PRL (19%), and GH-PRL and a glycoprotein hormone, usually TSH and/or α-subunit (76%). Of the 10 adenoma-containing lesions subject to electron microscopy (EM), 2 consisted of GH cells alone; 2 of mammosomatotroph (MS) cells alone; 1 of GH and MS cells; 1 of GH and PRL cells; 2 of GH, PRL, and MS cells; 1 of GH, PRL, and glycoprotein cells; and 1 was a subtype 3 adenoma. Ultrastructurally, GH cells and/or MS cells predominated in these lesions. Immuno-EM of one GH and PRL cell and of one GH-PRL-MS tumor showed GH and PRL to be present not only in single cells but within the same granules. Nine of 12 adenoma-associated lesions subject to combinedin situ hybridization (ISH) and immunostaining showed double labeling for PRL (or GH) mRNA and for GH (or PRL), respectively, features indicating MS differentiation. In the 4 lesions exhibiting hyperplasia, either alone (1) or in association with adenoma (3), EM showed MS cells in 3, and immuno-EM as well as combined immunohistochemistry and ISH showed double labeling for GH and PRL in both of the 2 cases studied. In summary, although in terms of their tinctorial characteristics and tumor size, the lesions of giants resemble those of acromegalics, those of the former are less often invasive and glycoprotein hormone containing, and more often contain ultrastructurally distinctive MS cells. The high frequency of adenoma with hyperplasia (37%) and the occurrence of hyperplasia alone (6%) is of particular notice since this finding is rare in patients with acromegaly. Hyperplasia is, however, seen in ectopic GH-releasing hormone production and the McCune-Albright syndrome. We conclude that the presence of MS is not rare in the pituitary lesions of patients with gigantism. Their presence may be a reflection of either hypothalamic dysfunction or of an intrinsic abnormality of pituitary cells.     

Cushing's Syndrome from an Ectopic Pituitary Adenoma with Peliosis: A Histological,Immunohistochemical, and Ultrastructural Study and Review of the Literature

Ectopic pituitary adenoma (EPA) is rare and, to the authors’ knowledge, its association with peliosis has not yet been described. The case of a 38-yr-old woman with clinical and biochemical evidence of Cushing’s syndrome is reported. Magnetic resonance imaging (MRI) disclosed a normal pituitary and a separate mass in the sphenoid sinus. The surgically remove’s hyaline change in the corticotrophs, indicating exposure to glucocorticoid excess. By histology, the mass in the sphenoid sinus was a congested, chromophobic, partly basophilic, periodic acid-Schiff (PAS)-positive pituitary adenoma composed of pleomorphic, adrenocorticotropic hormone (ACTH)-positive, corticotrophs. There was focal immunopositivity for MIB-1 and proliferating cell nuclear antigen (PCNA). Electron microscopy confirmed the diagnosis of corticotroph adenoma. A striking finding, consistent with the diagnosis of peliosis, was the presence of multiple large blood-filled spaces lacking an endothelial lining. The capillaries were dilated, but often appeared empty and the fenestrated endothelium exhibited discontinuities. The cause of peliosis is obscure. It may be that the venous outflow was impaired in this case leading to capillary dilation, congestion, hyperpermeability, rupture, and accumulation of blood in extravascular spaces.     

Pituitary carcinoma with intraspinal metastasis: report of two cases and review of the literature

Pituitary carcinomas are rare malignant neoplasms with diagnostic and management challenges. Patients with pituitary carcinomas have extremely poor outcomes. In this report, the authors describe two cases of pituitary carcinomas with intraspinal metastasis (Case 1: 42-year-old man with a history of pituitary adenoma 16 years ago developed an intraspinal lesion at C4-C5; Case 2: 26-year-old women with a history of growth hormone-producing pituitary adenoma 9 years ago developed intraspinal lesion in the sacral canal). Both patients underwent spine surgery. The intraspinal lesions were confirmed as metastatic pituitary carcinomas based on the histomorphology and immunohistochemical stains. The authors reviewed the literature for the diagnosis, treatment, and prognosis of intraspinal metastasis from pituitary carcinomas.     

Malakoplakia and colonic adenoma: a rare association

We report the case of a 73-year-old woman who presented respectively a caecal adenocarcinoma, two high-grade dysplastic tubulo-villous adenomas of the right colon, and a well differentiated adenocarcinoma developed on a high-grade dysplastic tubulo-villous adenoma of the left colon. One of the right colonic adenomas was ulcerated and showed typical foci of malakoplakia in the lamina propria. Malakoplakia is a histiocytic inflammatory response that may be associated with inflammatory and infectious diseases, immunosuppressive therapy, or colorectal carcinoma. Association of malakoplakia with colonic adenoma is rare; only three cases have been described in the literature thus far. To verify if this association is more common than usually suspected, we reviewed 100 colonic adenomas measuring at least 2 cm. No other case of malakoplakia associated with adenoma was found. The patient did not suffer from any other inflammatory or infectious disease and she was not under any medication or immunosuppressive therapy. Our observation confirms the isolated association of malakoplakia and colonic adenomas and the rarity of this association.     

Detection of Heterozygous Mutation in the Retinoblastoma Gene in a Human Pituitary Adenoma Using PCR-SSCP Analysis and Direct Sequencing

Genomic deoxyribonucleic acid from surgical specimens of 25 pituitary adenomas was screened for the presence of mutations in the tumor suppressor gene, retinoblastoma gene, using polymerase chain reaction and single-strand conformation polymorphism analysis, followed by direct deoxyribonucleic acid sequencing. Mutation causing an amino acid change was found in one of the 25 pituitary adenomas. The mutation site was in exon 19 (codon 621) of the retinoblastoma gene. In addition, there were three types of silent mutations in introns of the gene. The patient in whom the retinoblastoma mutation was identified had a tumor with high clinical malignancy, a high percentage of c-myc protein-labeled cells, and a diagnosis of plurihormonal pituitary adenoma based on the presence of cells immunoreactive for five pituitary hormones. This article suggests that point mutation of retinoblastoma gene is rare in human pituitary adenomas but may provide a marker for aggressive pituitary adenoma.     

ACTH-producing pituitary adenoma in an infant with cysts of the kidneys and lungs

The light microscopical, electron microscopical and immunohistological features of a rare ACTH-producing chromophobe adenoma of the pituitary gland in an 11-month-old infant are presented. An unusual histological feature was the presence of numerous follicles. These follicles may develop secondary to necrosis of individual tumour cells. There is only one previous report in the literature of a pituitary adenoma occurring in infancy and that tumour also produced ACTH and showed a follicular histological pattern. It is of interest that our patient also had a combination of medullary cysts of the kidneys and congenital peripheral cysts of the lungs. The association of cysts in lungs with cysts in kidneys also has been reported only once previously. We conclude that the occurrence of cysts in kidneys and lungs and a pituitary tumour in infancy represents a bizarre coincidence although an unknown common embryonic insult to these organs cannot be ruled out.     

Basal cell adenoma with extensive squamous metaplasia and cellular atypia: a case report with cytohistopathological correlation and review of the literature

Basal cell adenoma (BCA) is a rare benign basaloid neoplasm of the salivary gland. There are four histopathological types of BCA: solid, tubular, trabecular, and membranous. It is known that focal squamous metaplasia may be seen in some BCAs, but it is rare to see extensive squamous metaplasia, especially with cellular atypia. Here, a 25-year-old male with right parotid swelling is presented. Ultrasonography revealed a 2-cm well defined mass in his parotid gland. Fine-needle aspiration (FNA), performed prior to surgical excision, showed a highly cellular tumor composed of basaloid cells, forming small duct-like or tubular structures containing basement membrane-like material, as well as squamous cells with hyperchromatic, enlarged, pleomorphic, and bizzare nuclei. We made a cytopathological diagnosis of "basaloid neoplasm" and also reported that the differential diagnosis included BCA, cellular pleomorphic adenoma, basal cell adenocarcinoma, and carcinoma ex pleomorphic adenoma. The patient underwent total parotidectomy. Both frozen and permanent sections showed a BCA with membranous, tubulotrabecular pattern, and extensive squamous metaplasia. Some of the squamous cells showed significant nuclear hyperchromasia, enlargement, and pleomorphism. As far as we know, this is the first case of BCA with extensive squamous metaplasia and prominent cellular atypia. This case has been presented to show that squamous metaplastic cells with hyperchromatic, enlarged, bizarre, and pleomorphic nuclei can be seen on FNA smears of a benign tumor like BCA. Also, the differential diagnosis of BCA of the salivary gland is discussed here.     

Clusterin Expression in Non-neoplastic Adenohypophyses and Pituitary Adenomas: Cytoplasmic Clusterin Localization in Adenohypophysis is Related to Aging

Clusterin is a circulating multifunctional glycoprotein produced in several kinds of epithelial and neuronal cells. Clusterin is upregulated during different physiological and pathological states, such as senescence, type-2 diabetes mellitus, Alzheimer disease, and in various neoplasms. Herein, we investigated the immunohistochemical expression of clusterin in non-neoplastic adenohypophysis of human autopsy subjects and pituitary adenomas. We also investigated the association of clusterin increase with age in adenohypophysis of autopsy subjects. Immunohistochemically, clusterin was found positive in the cytoplasm of all adenoma cases, and in the cytoplasm of parenchymal cells, stellate cells, mixed cell follicles and in colloidal material inside of the follicles of non-neoplastic adenohypophysis as well. Clusterin expression in pituitary adenomas was found significantly higher than in non-neoplastic adenohypophyses. In addition, in non-neoplastic adenohypophysis, a significant increase in clusterin expression levels between young (≤30 years), middle aged (31 to 60 years), and older (≥61 years) subjects (p < 0.00001, analysis of variance [ANOVA]) was found. In addition to clusterin accumulation, presence of calcification (p < 0.045, ANOVA) and presence of large follicles with colloid accumulation (p < 0.004, ANOVA) were also statistically significant factors related to aging in non-neoplastic adenohypophysis. In conclusion, the present study demonstrated that clusterin expression was found in non-neoplastic adenohypophysis and in upregulated amounts in pituitary adenomas. This study also demonstrated that in non-neoplastic adenohypophyses, increase of clusterin positive cells; histopathological findings of calcification or presence colloidal material accumulation in large follicles were associated with age. To our knowledge, immunohistochemical localization of clusterin in pituitary adenomas was not reported previously.     

Pituitary tumor transforming gene-1 haplotypes and risk of pituitary adenoma: a case-control study

Background  

It has been suggested that pituitary adenoma results from accumulation of multiple genetic and/or epigenetic aberrations, which may be identified through association studies. As pituitary tumor transforming gene-1 (PTTG1)/securin plays a critical role in promoting genomic instability in pituitary neoplasia, the present study explored the association of PTTG1 haplotypes with the risk of pituitary adenoma.     

Prolactin-producing pituitary adenoma associated with prolactin cell hyperplasia

A 24-yr-old woman with amenorrhea, galactorrhea, hyperprolactinemia, and sellar mass underwent transsphenoidal surgery. Histologic, immunohistochemical, and electron microscopic investigation revealed a well-differentiated, sparsely granulated prolactin (PRL) cell adenoma of the pituitary showing conclusive PRL immunoreactivity. In the nontumorous adenohypophysis PRL cell hyperplasia was noted. Marked differences were evident between the neoplastic and hyperplastic areas. The tumor consisted of sparsely granulated PRL cells immunoreactive only for PRL. As demonstrated by immunoelectron microscopy, the hyperplastic are a comprised monohormonal sparsely granulated PRL cells as well as bihormonal mammosomatotrophs immunoreactive for both PRL and growth hormone. The MIB-1 index was higher whereas microvessel density was lower in the adenoma as compared with the hyperplastic area. In addition, the nontumorous area showed lymphocytic infiltration whereas inflammatory reaction was not seen in the adenoma. This case represents a rare association of a PRL cell adenoma and PRL cell hyperplasia. The fact that these two lesions were contiguous in the surgically removed material raises the possibility that hyperplasia can precede and transform into adenoma.