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

An inverted hyperplastic polyp (IHP) found in stomach is rare and characterized by downward growth of hyperplastic mucosal component into the submucosa. Because of such characteristic, IHP can be misdiagnosed as subepithelial tumor or malignant tumor. In fact, adenocarcinoma was reported to have coexisted with gastric IHP in several previous reports. Because only 18 cases on gastric IHP have been reported in English and Korean literature until now, pathogenesis and clinical features of gastric IHP and correlation with adenocarcinoma have not been clearly established. Herein, we report a case of gastric IHP which was initially misdiagnosed as gastrointestinal stromal tumor and resected using endoscopic submucosal dissection. Literature review of previously published case reports on gastric IHP is also presented.
Adult ; Gastric Mucosa/pathology/surgery ; Humans ; Hyperplasia/*diagnosis/diagnostic imaging ; Male ; Polyps/pathology/surgery ; Stomach/diagnostic imaging ; Stomach Neoplasms/diagnosis/diagnostic imaging/pathology ; Tomography, X-Ray Computed ; Ultrasonography

Adenocarcinoma ; metabolism ; pathology ; Adenocarcinoma, Clear Cell ; metabolism ; pathology ; Adult ; Carcinoma, Endometrioid ; metabolism ; pathology ; Cervix Uteri ; metabolism ; pathology ; surgery ; Cyclin-Dependent Kinase Inhibitor p16 ; metabolism ; Diagnosis, Differential ; Electrosurgery ; Endometrial Neoplasms ; metabolism ; pathology ; Female ; Humans ; Hyperplasia ; Keratin-7 ; metabolism ; Mesonephros ; metabolism ; pathology ; surgery ; Neprilysin ; metabolism ; Uterine Cervical Neoplasms ; metabolism ; pathology

OBJECTIVETo analyze the clinicopathologic and immunohistochemical features of nodular histiocytic/mesothelial hyperplasia (NHMH) and to improve the knowledge of this disease.

METHODSSeven cases of NHMH were collected and the clinicopathologic and immunohistochemical data were analyzed with review of the literature.

RESULTSSeven male patients aged from 1.5 to 5.0 years (mean 2.8). The main clinical symptom was an inguinal mass.Grossly, main pathological changes were the mural nodule or free nodule in lumen, with diameter of 0.1-0.5 cm.Histologically, the tumor cell morphology was relatively single, cohesive polygonal or oval cells which were arranged in solid sheets or nests, usually with ovoid or deeply grooved nuclei and a moderate amount of pale pink cytoplasm in the nodular collection area. The nuclei had delicate chromatin and no obvious atypia, and mitosis was incidentally found. A few scattered lymphocytes were found in the stroma. The cyst wall was lined by a single layer of mesothelial cells.Immunohistochemically, the most cells in nodular lesion were strongly positive for the histiocytic marker CD68, vimentin and α1-antichymotrypsin, while lining mesothelial cells on the wall were positive for calretinin, MC, WT1, CK5/6, CKpan and EMA.

CONCLUSIONSNHMH is a rare and benign tumor-like lesion, and easy to be misdiagnozed, which should be distinguished from neuroendocrine tumors, Langerhans cell histiocytosis, seminoma, mesothelioma and so on. The correct diagnosis of this lesion depends on the clinical characteristics, morphology and immunohistochemistry.

Antigens, CD ; metabolism ; Antigens, Differentiation, Myelomonocytic ; metabolism ; Calbindin 2 ; metabolism ; Child, Preschool ; Diagnosis, Differential ; Epithelium ; metabolism ; pathology ; surgery ; Histiocytes ; metabolism ; pathology ; Histiocytosis, Langerhans-Cell ; metabolism ; pathology ; Humans ; Hyperplasia ; metabolism ; pathology ; surgery ; Infant ; Leukocyte Common Antigens ; metabolism ; Male ; Mesothelioma ; metabolism ; pathology ; Mucin-1 ; metabolism ; Neuroendocrine Tumors ; metabolism ; pathology ; Seminoma ; metabolism ; pathology ; Vimentin ; metabolism ; WT1 Proteins ; metabolism ; alpha 1-Antichymotrypsin ; metabolism

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

OBJECTIVETo study the clinicopathologic features, diagnosis and differential diagnosis of epithelioid hemangioma.

METHODSThe morphologic features of 7 cases of epithelioid hemangioma of skin, bone and venous vessels were studied.

RESULTSThere were altogether 4 male and 3 female patients (median age = 34 years; age range from 14 to 54 years). The 3 skin cases presented as single or multiple erythematous to bluish nodules or papules, with or without itchiness. The 2 bone cases appeared as osteolytic expansile lesions on radiologic examination. The remaining 2 cases involved medium-sized venous structures and presented as small isolated nodules in soft tissue. Histologically, the lesions were characterized by the presence of exuberant endothelial proliferations with various degree of inflammatory reaction. The neoplastic endothelial cells were plump, eosinophilic and polygonal, forming vascular channels. Occasional solid sheet-like arrangement was demonstrated. Intracytoplasmic vacuoles were commonly identified, indicating formation of primary lumen. The surrounding stroma contained various number of eosinophils and lymphoplasmacytic cells. Immunohistochemical study showed that the tumor cells were positive for endothelial markers (CD31 and CD34) and negative for epithelial marker (cytokeratin). Follow-up information was available in 6 cases. The duration of follow-up ranged from 5 to 36 months (median = 14 months). There was no evidence of recurrence or distant metastasis.

CONCLUSIONSEpithelioid hemangioma is a rare benign curable lesion which can be multifocal, involving skin, soft tissue and bone. It needs to be distinguished from Kimura's disease and epithelioid hemangioendothelioma.

Adolescent ; Adult ; Angiolymphoid Hyperplasia with Eosinophilia ; pathology ; Antigens, CD34 ; metabolism ; Bone Neoplasms ; metabolism ; pathology ; surgery ; Diagnosis, Differential ; Female ; Follow-Up Studies ; Hemangioendothelioma, Epithelioid ; pathology ; Hemangioma ; metabolism ; pathology ; surgery ; Humans ; Male ; Middle Aged ; Platelet Endothelial Cell Adhesion Molecule-1 ; metabolism ; Skin Neoplasms ; metabolism ; pathology ; surgery

Diagnosis, Differential ; Endothelium, Vascular ; metabolism ; pathology ; Female ; Humans ; Hyperplasia ; Jejunal Diseases ; metabolism ; pathology ; surgery ; Jejunum ; blood supply ; pathology ; surgery ; Middle Aged ; Platelet Endothelial Cell Adhesion Molecule-1 ; metabolism

No abstract available.
Aged ; Biological Markers/blood ; Biopsy ; Calcium/blood ; Female ; Humans ; Hyperparathyroidism/blood/diagnosis/*etiology/surgery ; Hyperplasia ; Parathyroid Glands/metabolism/*pathology/radionuclide imaging/surgery/ultrasonography ; Parathyroid Hormone/blood ; Parathyroid Neoplasms/blood/*complications/diagnosis/surgery ; Parathyroidectomy ; Treatment Outcome ; Up-Regulation

OBJECTIVETo study the clinicopathologic features of primary thymic extranodal marginal zone B-cell lymphoma of mucosa-associated lymphoid tissue (MALT).

METHODSThe clinical and pathologic findings were evaluated in 3 cases of biopsy confirmed thymic MALT lymphoma. The clincopathologic features, treatment and prognosis were discussed and literatures reviewed.

RESULTSOne male and two female patients presented with asymptomatic mediastinal masses with a history of Sjögren syndrome. They were aged 36, 35 and 41 years respectively, and only one patient had B symptoms. Grossly, all three tumors were encapsulated and had multiple variable-sized cysts on cut-surface. Histopathologically, the normal thymic lobular architecture was effaced by abnormal dense lymphoid infiltration. Prominent lymphoepithelial lesions were formed by centrocyte-like cells infiltrating and expanding Hassall's corpuscles and epithelial cyst lining. All cases showed apparent plasmacytic differentiation. Immunohistochemically, the tumor cells were positive for CD20, CD79a, bcl-2 and negative for CD3, CD5, cyclin D1, CD43, CD10, bcl-6, and CD23. The plasma cells showed kappa light chain restriction. Immunoglobulin heavy chain rearrangement in three cases was confirmed by PCR. All patients were at early stage and received routine chemotherapy with or without radiotherapy after surgical removal. All patients achieved complete remission with 24, 18 and 3 months follow-up, respectively.

CONCLUSIONSPrimary thymic MALT lymphoma may be a rare distinctive lymphoma. It can be diagnosed by HE and immunohistochemical study and should be differentiated from reactive lymphoid proliferation, other types of lymphoma and mediastinal thymoma.

Adult ; Antibodies, Monoclonal, Murine-Derived ; therapeutic use ; Antigens, CD20 ; metabolism ; Antineoplastic Combined Chemotherapy Protocols ; therapeutic use ; Cyclophosphamide ; therapeutic use ; Diagnosis, Differential ; Doxorubicin ; therapeutic use ; Female ; Follow-Up Studies ; Gene Rearrangement, B-Lymphocyte, Heavy Chain ; Humans ; Immunoglobulin Heavy Chains ; genetics ; Keratin-19 ; metabolism ; Lymphoma, B-Cell, Marginal Zone ; drug therapy ; genetics ; metabolism ; pathology ; surgery ; Male ; Prednisone ; therapeutic use ; Pseudolymphoma ; pathology ; Thymus Hyperplasia ; pathology ; Thymus Neoplasms ; drug therapy ; genetics ; metabolism ; pathology ; surgery ; Vincristine ; therapeutic use