Owing to the progress of imaging techniques, benign hepatocellular nodules are increasingly discovered in the clinical practice. This group of lesions mostly arises in the context of a putatively normal healthy liver and includes either pseudotumoral and tumoral nodules. Focal nodular hyperplasia and hepatocellular adenoma are prototypical examples of these two categories of nodules. In this review we aim to report the main pathological criteria of differential diagnosis between focal nodular hyperplasia and hepatocellular adenoma, which mainly rests upon morphological and phenotypical features. We also emphasize that for a correct diagnosis the clinical context such as sex, age, assumption of oral contraceptives, associated metabolic or vascular disturbances is of paramount importance. While focal nodular hyperplasia is a single entity epidemiologically more frequent than adenoma, the latter is representative of a more heterogeneous group which has been recently and extensively characterized from a clinical, morphological, phenotypical and molecular profile. The use of the liver biopsy in addition to imaging and the clinical context are important diagnostic tools of these lesions. In this review we will survey their systematic pathobiology and propose a diagnostic algorithm helpful to increase the diagnostic accuracy of not dedicated liver pathologists. The differential diagnosis between so-called typical and atypical adenoma and well differentiated hepatocellular carcinoma will also be discussed.
Adenoma/*diagnosis/surgery ; Carcinoma, Hepatocellular/diagnosis ; Diagnosis, Differential ; Focal Nodular Hyperplasia/*diagnosis/surgery ; Hepatocyte Nuclear Factor 1-alpha/metabolism ; Humans ; Liver/pathology ; Liver Neoplasms/*diagnosis/surgery ; beta Catenin/genetics/metabolism

Owing to the progress of imaging techniques, benign hepatocellular nodules are increasingly discovered in the clinical practice. This group of lesions mostly arises in the context of a putatively normal healthy liver and includes either pseudotumoral and tumoral nodules. Focal nodular hyperplasia and hepatocellular adenoma are prototypical examples of these two categories of nodules. In this review we aim to report the main pathological criteria of differential diagnosis between focal nodular hyperplasia and hepatocellular adenoma, which mainly rests upon morphological and phenotypical features. We also emphasize that for a correct diagnosis the clinical context such as sex, age, assumption of oral contraceptives, associated metabolic or vascular disturbances is of paramount importance. While focal nodular hyperplasia is a single entity epidemiologically more frequent than adenoma, the latter is representative of a more heterogeneous group which has been recently and extensively characterized from a clinical, morphological, phenotypical and molecular profile. The use of the liver biopsy in addition to imaging and the clinical context are important diagnostic tools of these lesions. In this review we will survey their systematic pathobiology and propose a diagnostic algorithm helpful to increase the diagnostic accuracy of not dedicated liver pathologists. The differential diagnosis between so-called typical and atypical adenoma and well differentiated hepatocellular carcinoma will also be discussed.
Adenoma/*diagnosis/surgery ; Carcinoma, Hepatocellular/diagnosis ; Diagnosis, Differential ; Focal Nodular Hyperplasia/*diagnosis/surgery ; Hepatocyte Nuclear Factor 1-alpha/metabolism ; Humans ; Liver/pathology ; Liver Neoplasms/*diagnosis/surgery ; beta Catenin/genetics/metabolism

Adenoma ; diagnosis ; surgery ; Aged ; Female ; Humans ; Magnetic Resonance Imaging ; Neoplasm Invasiveness ; Optic Chiasm ; pathology ; Pituitary Neoplasms ; diagnosis ; diagnostic imaging ; surgery ; Recurrence ; Treatment Outcome

We report a rare case of pleomorphic adenoma arising from the nasal septum. A 37-year-old woman presented with a 1-year-history of right-sided occasional epistaxis. Computed tomographic scans revealed an oval mass in the right nasal cavity. The tumor was removed endoscopically with endonasal approach. The microscopic finding showed numbers of myoepithelial cells and duct-like structures consisting of loose myxoid stroma. This lesion had histological characteristics of a pleomorphic adenoma, and this was confirmed by immunohistochemical expression of cytokeratin, S-100 protein and SMA. Her post-operative course was uneventful, and she is currently free from the disease 1.5 years after surgery.
Actins ; metabolism ; Adenoma, Pleomorphic ; diagnosis ; surgery ; Adult ; Endoscopy ; Epistaxis ; Epithelial Cells ; Female ; Humans ; Keratins ; metabolism ; Nasal Septum ; pathology ; Nose Neoplasms ; diagnosis ; surgery ; S100 Proteins ; metabolism

OBJECTIVETo study the clinicopathologic characteristics of parathyroid carcinoma (PTC).

METHODSEleven cases of PTC encountered during the period from 1994 to 2012 were enrolled into the study. Forty cases of parathyroid adenoma (PA) were also retrieved for comparison. The clinical manifestations, laboratory results and pathologic features were analyzed, with literature review.

RESULTSThe main clinical manifestations of PTC included neck mass (11/11), hypercalcemia (11/11) and hyperparathyroidism (11/11). Most patients also had osteoporosis (10/11). In contrast, PA often manifested as hypercalcemia (40/40) and hyperparathyroidism (40/40). Histologic examination of PTC showed that the tumor cells contained clear to eosinophilic cytoplasm and separated by dense bands of fibrosis. The tumor mass was surrounded by thick fibrous capsule. Foci of capsular invasion and vascular permeation were identified at the tumor periphery in all cases. Cellular atypia was not conspicuous but mitotic figures and coagulative necrosis were easily identified. On the other hand, PA were composed of tumor cells with clear to eosinophilic cytoplasm, forming glands, trabeculae or nests. Most of them (35/40) had intact fibrous capsule. Mitotic figures were rarely encountered and tumor necrosis was absent. Immunohistochemical study showed that the tumor cells in PTC were positive for CK19 (11/11), chromogranin A (9/11), synaptophysin (7/11) and parathyroid hormone (11/11). They were negative for thyroglobulin, TTF-1 and calcitonin. The Ki-67 index was less than 10% (range = 2% to 9%). In contrast, the tumor cells in PA were positive (40/40) for CK19, chromogranin A, synaptophysin and parathyroid hormone. They were negative for thyroglobulin, TTF-1 and calcitonin. The Ki-67 index was less than 3%. Follow up-data were available in 9 cases of PTC (duration of follow up = 11 months to 224 months) and 7 of the patients were still alive. Follow up of all PA cases showed no evidence of recurrence.

CONCLUSIONSPTC is a rare malignant endocrine tumor presenting as neck mass. Histologic features suggestive of malignant behavior include presence of coagulative tumor necrosis and capsular/vascular invasion. It needs to be distinguished from other entities such as parathyroid adenoma, papillary thyroid carcinoma and medullary thyroid carcinoma.

Adenoma ; metabolism ; pathology ; Adult ; Carcinoma ; metabolism ; pathology ; Carcinoma, Neuroendocrine ; Carcinoma, Papillary ; Chromogranin A ; metabolism ; Diagnosis, Differential ; Female ; Follow-Up Studies ; Humans ; Hypercalcemia ; etiology ; Hyperparathyroidism ; etiology ; Immunohistochemistry ; Keratin-19 ; metabolism ; Male ; Middle Aged ; Osteoporosis ; etiology ; Parathyroid Hormone ; metabolism ; Parathyroid Neoplasms ; complications ; metabolism ; pathology ; surgery ; Synaptophysin ; metabolism ; Thyroid Neoplasms ; metabolism ; pathology

OBJECTIVETo study the clinical and histopathologic features of metanephric adenoma (MA).

METHODSEight cases of recently diagnosed MA were retrieved from archival file. Immunohistochemical study was carried out. The clinical characteristics, pathologic parameters, differential diagnosis, treatment options and prognosis of MA were analyzed, with literature review.

RESULTSThe patients included 6 females and 2 males. The age of patients ranged from 12 to 70 years (mean=43.6 years). Eight cases were located in renal cortex and showed well-defined borders. Histologically, the tumor was composed of tubules lined by small basophilic cells and embedded in an edematous stroma. Papillary structures and psammoma bodies were focally seen. Immunohistochemical study showed that the tumor cells were positive for PAX2 and vimentin in all the 8 cases. WT-1 was positive in 2 cases, focal and weak in 5 cases, and negative in 1 case. CK-Pan was positive in 3 cases. CK7 staining was mostly negative, with focal and weak positivity only in 1 case. The proliferative index, as highlighted by Ki-67 staining, was less than 2% in 7 cases and focally around 5% in 1 case. The expressions of CK20, CD10, RCC, epithelial membrane antigen, CD56, synaptophysin and chromogranin A were negative. Follow-up information from 7 to 57 months was available in all patients; and none of them developed local recurrence or distant metastasis.

CONCLUSIONSThe diagnosis of MA relies primarily on thorough histologic examination and immunohistochemical study (vimentin and PAX2 positive, WT-1 focally and weakly positive in some cases, and low proliferative index). Correlation with clinical and radiologic findings would also be helpful.

Adenoma ; diagnostic imaging ; metabolism ; pathology ; surgery ; Adolescent ; Adult ; Aged ; Biomarkers, Tumor ; metabolism ; Carcinoma, Renal Cell ; metabolism ; pathology ; Child ; Diagnosis, Differential ; Female ; Follow-Up Studies ; Humans ; Kidney Neoplasms ; diagnostic imaging ; metabolism ; pathology ; surgery ; Male ; Middle Aged ; Nephrectomy ; methods ; PAX2 Transcription Factor ; metabolism ; Tomography, X-Ray Computed ; Vimentin ; metabolism ; WT1 Proteins ; metabolism ; Wilms Tumor ; pathology ; Young Adult

Focal nodular hyperplasia (FNH) is the second most common benign hepatic tumor that is usually found in women. Diagnosis of FNH mainly depends on imaging studies such as color Doppler flow imaging, computed tomography, and magnetic resonance imaging. It is characterized by the presence of stellate central scar and is nowadays incidentally diagnosed with increasing frequency due to advances in radiologic imaging technique. FNH typically presents as a single lesion in 70% of cases and generally does not progress to malignancy or recur after resection. Herein, we report a case of a young male patient with recurrent multiple FNH who underwent surgical resection for presumed hepatic adenoma on computed tomography.
Adenoma, Liver Cell/diagnosis/pathology ; Bile Ducts/pathology/surgery ; Contrast Media/diagnostic use ; Focal Nodular Hyperplasia/*diagnosis/pathology ; Humans ; Liver Neoplasms/*diagnosis/pathology ; Magnetic Resonance Imaging ; Male ; Neoplasm Recurrence, Local ; Tomography, X-Ray Computed ; Young Adult

Adenoma ; metabolism ; pathology ; surgery ; ultrastructure ; Adnexa Uteri ; pathology ; surgery ; Adnexal Diseases ; metabolism ; pathology ; surgery ; Carcinoma, Endometrioid ; metabolism ; pathology ; Diagnosis, Differential ; Female ; Granulosa Cell Tumor ; metabolism ; pathology ; Humans ; Hysterectomy ; Keratins ; metabolism ; Leiomyomatosis ; pathology ; surgery ; Microscopy, Electron ; Middle Aged ; Neoplasms, Multiple Primary ; metabolism ; pathology ; surgery ; ultrastructure ; Sertoli-Leydig Cell Tumor ; metabolism ; pathology ; Uterine Neoplasms ; pathology ; surgery ; Vimentin ; metabolism ; WT1 Proteins ; metabolism

Adenocarcinoma, Mucinous ; pathology ; Adenoma ; pathology ; Adolescent ; Breast Neoplasms, Male ; metabolism ; pathology ; secretion ; surgery ; Carcinoma ; metabolism ; pathology ; secretion ; surgery ; Diagnosis, Differential ; Humans ; Keratin-18 ; metabolism ; Keratin-8 ; metabolism ; Male ; Mastectomy, Modified Radical ; Proto-Oncogene Proteins c-kit ; metabolism ; S100 Proteins ; metabolism

Adenoma ; pathology ; Brain Neoplasms ; secondary ; Chromogranin A ; metabolism ; Diagnosis, Differential ; Follow-Up Studies ; Humans ; Magnetic Resonance Imaging ; Male ; Middle Aged ; Neoplasm Recurrence, Local ; Pituitary Neoplasms ; diagnosis ; metabolism ; pathology ; surgery ; Reoperation ; Synaptophysin ; metabolism ; Temporal Lobe ; pathology