Struma ovarii, the most common monodennal teratoma of the ovary, causes diverse problems in differential diagnosis. The literature on the pathology of struma ovarii has focused principally on the problem of formulating criteria of malignancy. In contrast, unusual gross and microscopic features of struma ovarii and its resultant problems in differential diagnosis have received relatively little attention. We report an ovarian teratoma which was almost entirely cystic, causing the diagnosis of struma to be overlooked. The removed ovarian tumor showed all the features of adenomatous goiter of the thyroid gland. The lining epithelium of the cysts was frequently flattened, and the follicles in the cyst wall were few and atrophic. The patient was a 58-year-old woman who was found to have an ovarian tumor by routine monographic examination
Diagnosis ; Diagnosis, Differential ; Epithelium ; Female ; Goiter* ; Humans ; Middle Aged ; Ovary ; Pathology ; Struma Ovarii* ; Teratoma ; Thyroid Gland*

Sarcomatoid renal cell carcinoma is an uncommon tumor that has to be distinguished from renal carcinosarcoma. We have described three cases of sarcomatoid renal cell carcinoma showing different clinical and light microscopic features. An ultrastructural study of the tumor cells from the sarcomatoid area revealed frequent desmosomal junction, confirming the epithelial nature of the neoplasm. All three cases showed an aggressive clinical course and tended to invade adjacent organs or tissues. We believe that an histological and immunohistochemical examination in conjunction with an electron microscopic examination are necessary to diagnose sarcomatoid renal cell carcinoma.
Carcinoma, Renal Cell* ; Carcinosarcoma* ; Desmosomes ; Microscopy, Electron

The ductal system of the pancreas, which is responsible for carrying acinar secretion to the duodenum, is perhaps the smallest epithelial component of the pancreas. However, most pancreatic tumors are of ductal origin, and a majority of these are ductal adenocarcinomas. Pancreatic carcinomas of ductal type can be separated into several categories: 1. Conventional ductal adenocarcinoma (tumors that form small tubular glands with luminal and intracellular mucin and are associated with marked stromal desmoplasia). 2. Unusual histological patterns of conventional ductal adenocarcinoma (e.g., foamy gland pattern, large duct pattern, vacuolated pattern, lobular carcinoma-like pattern). 3. Other carcinomas of ductal origin (e.g., colloid carcinoma, adenosquamous carinoma, squamous cell carcinoma, and undifferentiated carcioma). Most tumors in this last category usually have an associated component of conventional ductal adenocarcinoma, which provides evidence of their ductal origin. Precursors of pancreatic ductal adenocarcinoma have been recognized as proliferative epithelium of the ducts. Some lesions with minimal cytologic atypia were not regarded to be neoplastic and were designated hyperplasia or metaplasia, but molecular study revealed most ductal proliferative lesions as neoplastic. Thus the entire spectrum of ductal proliferative lesion is referred to as pancreatic intraepithelial neoplasia (PanIN).
Adenocarcinoma ; Adenocarcinoma, Mucinous ; Carcinoma, Pancreatic Ductal ; Carcinoma, Squamous Cell ; Classification* ; Duodenum ; Epithelium ; Hyperplasia ; Metaplasia ; Mucins ; Pancreas ; Pancreatic Ducts ; Pancreatic Neoplasms ; Phenobarbital ; Precancerous Conditions

Hobnail hemangioma(HH) is a benign acquired vascular tumor of endothelial origin which should be differentiated from other malignant vascular neoplasm such as Kaposi's sarcoma or angiosarcoma. We report a case of hobnail hemangioma in a 21-year-old woman who had a dusky-red patch on her left shin. Histologically, ectatic vascular channels with a single layer of plumped endothelial cells were seen and the vascular channels seemed to dissect the collagen bundles. She underwent treatment with surgical excision with primary closure.
Collagen ; Endothelial Cells ; Female ; Hemangioma* ; Hemangiosarcoma ; Humans ; Sarcoma, Kaposi ; Vascular Neoplasms ; Young Adult

Atypical cutaneous fibrous histiocytoma (ACFH) is not well known and only a small number of cases have been reported. Characteristically, ACFH is found on the trunk and limbs of middle-aged women. Although considerable cellular atypia may be present, it occurs focally, the remainder of the tumor representing more classical cutaneous fibrous histiocytoma. A 37-year-old woman presented with a solitary brownish firm nodule on her right forearm. No other abnormalities were found in her personal or family history. Clinically, the tumor simulated a benign fibrous histiocytoma. Histologic examination revealed a poorly delineated intradermal tumor with the usual appearance of benign cutaneous fibrous histiocytoma, but a variable pro-portion of cells in the tumor were scattered atypical cells or bizarre multinucleated giant cells. We report upon a rare case of ACFH.
Adult ; Extremities ; Female ; Forearm ; Giant Cells ; Histiocytoma, Benign Fibrous* ; Humans

Cerebral amyloid angiopathy (C.A.A) is characterized by the extracellular amyloid protein deposition in the vessel walls of the brain and meninges. It has been estimated to account for 5 to 10% of all primary, nontraumatic brain hemorrhage. We report two cases of C.A.A causing nontraumatic intracerebral hemorrhage in the frontal lobe. The first case was a 60-year-old female who was admitted for the left hemiplegia and dysarthralgia. Brain CT revealed right frontal lobe hemorrhage. The second case was a 72-year-old male who was admitted for amnesia and gait disturbance. Clinical impression was Alzheimer's disease. Brain MRI revealed multifocal small hemorrhage in the right frontal lobe. Microscopically, both cases showed dilated small arteries of superficial cortex and meninges with hyalinization. Some vessels showed microaneurysm and fibriniod necrosis. Congo-red stain also exhibited birefringence under polarized light. There was no evidence of Alzheimer's disease.
Aged ; Alzheimer Disease ; Amnesia ; Amyloid ; Arteries ; Birefringence ; Brain ; Cerebral Amyloid Angiopathy* ; Cerebral Hemorrhage ; Female ; Frontal Lobe ; Gait ; Hemiplegia ; Hemorrhage ; Humans ; Hyalin ; Intracranial Hemorrhages ; Magnetic Resonance Imaging ; Male ; Meninges ; Middle Aged ; Necrosis

Pancreas cystic neoplasm is a relatively common disease. However, its' pathologic diagnosis is not easy. The most frequent problem is low cellularity when compared to another organ cytology or biopsy material. Considering the procedure and anatomic difficulty, it is not uncommon to observe a low cellular smear or scanty volume of cells in the biopsy specimen. In this case, the molecular pathology test, including next-generation sequencing, may be helpful. If pathologist can identify some mutation in cells or cystic fluid, differential diagnosis of cystic neoplasm may be possible. These are KRAS and GNAS, VHL, and CTNNB1 mutation in mucinous cystic neoplasm, intraductal papillary-mucinous neoplasm, serous cystic neoplasm, and solid pseudopapillary neoplasm, respectively. The next-generation sequencing is an emerging molecular test that can detect multiple biomarkers for diagnosis, including pancreas cystic neoplasm. It has been reported that next-generation sequencing test can be applied for differential diagnosis of pancreas cystic neoplasm. However, these molecular pathology tests were not all-around; it needs to be properly managed with pathologist's quality control. It should be remembered that even if it goes through quality control, it may show a failure rate of around 30%. Despite the advances in molecular methods of high techniques, it should be remembered that the most important thing in pathologic diagnosis of pancreas cystic neoplasm is an endoscopist's skill and pathologist's expertise those provide adequate specimen and accurate diagnosis.
Biomarkers ; Biopsy ; Diagnosis ; Diagnosis, Differential ; High-Throughput Nucleotide Sequencing ; Mucins ; Pancreas ; Pancreatic Cyst ; Pathology, Molecular ; Quality Control

Ampulla of Vater (AoV) is a small dilated duct less than 1.5 cm long, formed by the union of pancreatic duct and common bile duct. AoV has also anatomic layer of mucosa, sphincter of Oddi, perisphincteric or duodenal submucosa, and duodenal proper muscle, which corresponds to mucosa, muscularis mucosa, submucosa, and proper muscle layer of other gastrointestinal tract organs, respectively. Because of its small compact size and variation of anatomic structure, it is sometimes difficult to identify layering architecture of AoV. This anatomic difficulty may cause some problem in T classification of ampullary carcinoma (AC). The most confusing point in T classification is the vague definition of T2, "Tumor invades duodenal wall". It seems that duodenal wall includes duodenal mucosa, submucosa, and proper muscle layer. However there is no precise description or definition about duodenal wall that might lead personal variation in T classification of AC staging. We found that clinical course of AC with perisphincteric and/or duodenal submucosal invasion is more close to AC with T2 than T1. Although it is described as T1b according to T classification scheme of ordinary gastrointestinal tract cancer, we thought AC with T1b may have more high-grade malignant potential than those of other gastrointestinal (GI) tract malignancy. AC showed various clinicopatholgic findings that represent heterogeneous tumor groups within category of AC. Recently site-specific classification of AC was introduced, and it showed relatively well-categorized clinical prognosis. It may be reasonable to understand site-specific tumorigenesis in AC. The standard gross protocol is needed to evaluate pathologic T classification of AC. In conclusion, ampullary neoplasm is composed of various subtypes, which require a separate approach according to anatomic epicenter of ampullary neoplasm. Although submucosal invasion in AC was classified into pT1b, its' biologic behavior is more close to pT2.
Ampulla of Vater ; Carcinogenesis ; Classification ; Common Bile Duct ; Duodenum ; Gastrointestinal Neoplasms ; Gastrointestinal Tract ; Humans ; Mucous Membrane ; Neoplasm Staging ; Pancreatic Ducts ; Prognosis ; Sphincter of Oddi

Pathologic interpretation of endoscopic ultrasound–guided fine needle aspiration (EUS-FNA) cytology/biopsy specimens is one of the most challenging tasks in cytology and surgical pathology practice, as the procedure often yields minimal amounts of diagnostic material and contains contaminants, such as blood cells and normal intestinal mucosa. EUS-FNA cytology/biopsy will nevertheless become a more popular procedure for evaluation of various pancreatic lesions because they are difficult to approach with conventional endoscopic procedures. Pathologists should understand the structural differences and limitations of EUS-FNA that make pathologic diagnosis difficult. Ancillary tests are available for differential diagnosis of EUS-FNA for various pancreatic lesions. Immunostains are the most commonly used ancillary tests, and pathologists should able to choose the necessary panel for differential diagnosis. Pathologists should review clinical history and radiologic and/or EUS findings before selecting an immunostain panel and making a pathologic diagnosis. In addition, one’s threshold of malignancy should be adjusted according to the appropriate clinical setting to avoid under-evaluation of pathologic diagnoses. Clinico-pathologic correlation is essential in pathologic evaluation of EUS-FNA for pancreatic lesions. Pathologists can reduce errors by correlating clinical and radiologic findings when evaluating EUS-FNA. Some molecular tests can be applied in differential diagnosis of pancreatic neoplastic and cystic lesions. Molecular data should be used as supportive evidence of a specific disease entity, rather than direct evidence, and should be correlated with clinico-pathologic findings to avoid errors in pathologic diagnosis.

BACKGROUND: Usually, a malignant intraductal papillary mucinous tumor (IPMT) of the pancreas shows invasive carcinoma. Recently, IPMT with an unusual growth pattern of a fistulous extension was reported. However, little is known about malignant IPMTs with a different growth pattern of invasion and fistulous extension. METHODS: Malignant IPMTs were classified into invasive (colloid or tubular type) carcinomas and the fistulous extension type according to their growth patterns. Their clinicopathological characteristics were compared. RESULTS: Among a total of 68 cases of IPMT, there were 16 cases with malignant IPMT; eight, six and two of the colloid, tubular, and fistulous extension types, respectively. The immunohistochemical (IHC) expression of MUC1 was found in seven out of eight colloid and five out of six tubular types, but there was no IHC expression of MUC1 in the fistulous extension type. The IHC expression of MUC2 was noted in one of the eight colloid, one of the six tubular and in both cases with the fistulous extension type. There was no difference in the tumor recurrence rates bet- ween the different growth patterns. CONCLUSIONS: IPMT with the fistulous extension type has a peculiar extension pattern consisting of multiple fistulous tracts without a mass. Although most of the epithelium in the fistulous tract show moderate to severe dysplasia, only the fistulous extension should be considered to be an unusual growth pattern of malignant IPMT. The clinical significance of this unusual type of IPMT remains to be determined.
Colloids ; Epithelium ; Mucins* ; Pancreas* ; Recurrence