Peritoneal adenomatoid (microcystic) mesothelioma.

There are several reports of pleural adenomatoid (microcystic) mesothelioma, but peritoneal adenomatoid mesothelioma is extremely rare. A 64-year-old Japanese woman presented with no symptoms and no asbestos exposure history. An abdominal computed tomography scan revealed multiple hypervascular masses on the liver surface, pelvic cavity and anterior peritoneum. Over 10 pieces of the multiple resected tumors showed numerous microcysts composed of a bland mesothelial cell background with rich capillary vessels. Focally, atypical cells with bizarre nuclei with prominent nucleoli were observed. Adenomatoid mesothelioma was suspected based on histochemical, immunohistochemical and fluorescence in situ hybridization findings. The tumors relapsed 4 years later and metastasized to the lung, but the patient remains alive 7 years after the first tumor resection surgery. Although the prognosis of adenomatoid mesothelioma of pleural origin is poor, the progression of this peritoneal case is slow.

Pleural lymphoma combined with pleural sarcoidosis.

A patient with sarcoidosis was found to have a massive left pleural effusion. Her chest computed tomography showed small nodules in the lung parenchyma and swelling of the hilar lymph nodes, with normal visceral and parietal pleura. Thoracoscopy showed white nodules on the visceral pleura and normal parietal pleura, which were resected. Epithelioid granulomas were seen in the visceral pleura and lung parenchyma. Surprisingly, in the parietal pleura, abnormal cells that were positive for the leukocyte common antigen, CD20, and CD79a were found, leading to the diagnosis of malignant B-cell lymphoma.

Collision tumor of a papillary and follicular thyroid carcinoma: a case report.

BACKGROUND: Papillary thyroid carcinoma (PTC) and follicular thyroid carcinoma (FTC) are common differentiated thyroid cancers, but the detection of a collision tumor is an extremely rare event. CASE PRESENTATION: The patient was a 69-year-old Japanese female with multiple cervical lymph node swellings and a thyroid tumor. Preoperative fine needle aspiration cytology of the enlarged lymph node revealed a cytological diagnosis of papillary thyroid carcinoma (PTC). A total thyroidectomy, right cervical dissection and paratracheal dissection were performed. Histopathological and immunohistochemical analyses of resected specimens revealed a collision tumor of PTC and FTC. Multiple metastases of papillary carcinoma were found in the dissected lymph nodes. In the PTC lesion, IHC for BRAF (V600E) was positive but negative for the FTC lesion. Genetic analyses further revealed a TERT promoter C228T mutation in PTC and a NRAS codon 61 mutation in FTC. The patient died of recurrent cancer 8 months after surgery. CONCLUSIONS: A case of a collision tumor of PTC and FTC is very rare, and even fewer cases have been subjected to genetic scrutiny. The present case was successfully diagnosed by pathological examination using immunohistochemical and genetic analyses. The TERT promoter mutation in the PTC lesion was consistent with the aggressive behavior of the cancer.

Metachronous aortic aneurysms due to sarcoidosis.

A 62-year-old male developed metachronous aortic aneurysms at different locations over an interval of one year and three months. He was diagnosed to have sarcoid aneurysms due to the presence of noncaseating epithelioid granulomas in the aortic wall and lymph nodes. The patient was treated with steroids, but his sarcoidosis progressed gradually and extended into other major organs, and the lungs and heart were clinically determined to have been involved by sarcoidosis. He died of cardiac tamponade four years after the first operation for an aortic aneurysm.

Collagenous Colitis Possibly Associated with Dipeptidyl Peptidase-4 Inhibitor.

A 60-year-old man with type 2 diabetes mellitus treated with a dipeptidyl peptidase-4 (DPP-4) inhibitor was referred to our hospital because of his refractory watery diarrhea. Ileocolonoscopy revealed increased capillary growth, fine granular mucosa, and longitudinal mucosal tears mainly in the left side of the colon. A bioptic examination revealed thickened subepithelial collagen bands, thus confirming the diagnosis of collagenous colitis. Systemic steroid therapy was initiated, but his symptoms recurred when tapering the steroid. However, withdrawal of the DPP-4 inhibitor was successful even after the cessation of steroid therapy. We therefore considered his collagenous colitis to have been caused by the DPP-4 inhibitor.

ALK rearrangement-associated renal cell carcinoma morphologically mimicking mucinous tubular and spindle cell carcinoma: a case report.

BACKGROUND: Anaplastic lymphoma kinase rearrangement-associated renal cell carcinoma (ALK-RCC) is an extremely rare tumor and ALK-RCC that mimics mucinous tubular and spindle cell carcinoma (MTSCC) has been very reported only in one instance. CASE PRESENTATION: A 42-year-old Japanese woman was admitted to our hospital for the treatment of a left renal tumor measuring 5 cm in maximum dimension. She underwent a laparoscopic left nephrectomy. Histologically, the tumor formed tubular or focally papillary structures with a small amount of spindle-shaped tumor cells against the background of prominent extracellular mucin. Although the tumor cells were negative for immunohistochemistry (IHC) of alpha-methylacyl-CoA racemase (AMACR) and lymph node metastasis was presented (these are atypical findings for MTSCC), we initially diagnosed the tumor as MTSCC based on its morphological characteristics with mucin deposition. However, an additional IHC analysis revealed that the tumor cells were diffusely positive for ALK-IHC. In addition, TPM3 exon 8 - ALK exon 20 fusion gene was detected by RNA sequencing. The tumor was thus correctly diagnosed as ALK rearrangement-associated renal cell carcinoma (ALK-RCC). CONCLUSIONS: Since the use of molecular targeted therapy with an ALK inhibitor for ALK-RCC is promising, the correct pathological diagnosis of ALK-RCC is quite important. We strongly recommend that ALK-IHC be routinely performed for renal tumors with negative AMACR staining that mimic MTSCC.

Malignant lymphoma incidentally diagnosed due to the perforation of the small intestine caused by a fish bone: A case report.

INTRODUCTION: The ingestion of a foreign body is relatively common. However, it rarely results in the perforation of gastrointestinal tract. We herein report an unusual case of malignant lymphoma incidentally diagnosed after the perforation of the small intestine by a fish bone. PRESENTATION OF CASE: A 90-year-old woman was admitted to our hospital because of abdominal pain and vomiting. Abdominal computed tomography demonstrated free air and ascites in the abdominal cavity. In the pelvic cavity, a radiopaque linear shadow about 35mm in diameter was shown in the small intestine, and the stricture was exposed to the abdominal cavity. Therefore, a diagnosis of perforation of the small intestine due to ingestion of a foreign body and panperitonitis was made. Emergent laparotomy was performed. The intraoperative findings revealed perforation of the small intestine with a fish bone in the jejunum. Local inflammation at the perforation site was seen, and circulated wall thickness was observed at the distal side of the jejunum. Partial resection of the jejunum and anastomosis of jejuno-jejunostomy was performed. A pathological examination and immunohistochemical study of the resected specimen resulted in a diagnosis of malignant lymphoma of follicular lymphoma Grade 1. DISCUSSION: It is very difficult to identify the existence malignancy accompanied with gastrointestinal perforation with ingestion of a foreign body. CONCLUSION: In cases suspected of involving malignancy, careful observation during surgery is needed in order to avoid missing the accompanying malignancy.

Eosinophilic funiculitis initially diagnosed as irreducible inguinal hernia: A case report.

BACKGROUND: Most groin masses are first suspected to be groin hernias. More than 80% of bulging groin lesions are reportedly diagnosed as hernias by ultrasonography. Establishment of the correct diagnosis of hernia among all differential diagnoses is not easy. We herein describe a very rare case of groin eosinophilic funiculitis that presented as an irreducible groin hernia. CASE PRESENTATION: A 59-year-old man presented to our hospital with suspicion of a right groin hernia. He had a 1-week history of a painful right groin tumor. The tumor was about 4 cm without skin redness or warmth, irreducible even in the supine position, and associated with mild tenderness. Enhanced computed tomography showed that the mass seemed to be connected to the intra-abdominal structures. With time, the patient's pain did not increase, the inflammatory response did not worsen, and no ischemic signs were observed by enhanced computed tomography. Therefore, we diagnosed the tumor as an irreducible but not incarcerated hernia and performed elective surgery. Intraoperative examination revealed no hernia sac, and a 4-×3-cm tumor was observed around the spermatic cord. A malignant tumor was not completely ruled out. High orchiectomy was performed after consultation with the urologists. Pathological examination of the tumor showed no malignant features, and the final diagnosis was eosinophilic funiculitis with massive inflammatory changes and eosinophil invasion. CONCLUSION: Eosinophilic funiculitis is very rare; only three cases have been reported to date. We should always consider unusual causes of groin masses during a surgical approach to hernia-like lesions.

The relationship between primary gastric B-cell lymphoma and immunoglobulin heavy chain (IgH) gene rearrangement--a histopathological study of primary gastric lymphomas.

The aim of this study was to review our primary gastric lymphoma cases according to the new WHO classifications and to investigate the histopathological features of B-cell lymphomas. In addition, B-cell monoclonality was analyzed for immunoglobulin heavy chain (IgH) gene rearrangement using the polymerase chain reaction at the site of the lymphoma lesion, transitional lesion, and the non-lymphoma lesion. Specimens resected from 31 primary gastric lymphomas were examined. There were 28 cases (90.3%) of B-cell lymphoma and three cases (9.7%) of T-cell lymphoma. The B-cell lymphomas were classified as low-grade mucosa-associated lymphoid tissue (MALT) lymphoma (LGML) (9%), high-grade MALT lymphoma (HGML) (42%), and diffuse large B-cell lymphoma (DLBCL) (29%). Histopathologically, lymphoepithelial lesions (LEL) were higher in LGML (100%) than in DLBCL (22%), with statistical significance (p < 0.05). A monoclonal pattern of IgH rearrangement was detected in LGML (50.0%), HGML (60.0%), and DLBCL (80.6%), with a statistically significant difference between LGML and DLBCL (p < 0.01). The IgH monoclonal pattern may reflect the gross appearance of lymphoma or the lymphoma infiltration depth. Superficial spreading and shallow growth in LGML may correspond to an oligoclonal pattern, and mass-forming and deep invasive growth in DLBCL may correspond to a more monoclonal pattern.

[A case of para-aortic lymph node recurrence of gallbladder cancer completely responding to single drug (UFT) chemotherapy].

A 67-year-old man with gallbladder cancer was treated by cholecystectomy and extrahepatic bile duct resection with regional lymph node dissection. At 10 months after surgery, CT demonstrated para-aortic lymph node recurrence. Single drug chemotherapy of UFT at 400 mg was started. After one month, the lymph node recurrence could not be detected by CT. UFT may be the primary candidate for chemotherapy for lymph node recurrence of gallbladder cancer.

Genomic regions of pufferfishes responsible for host specificity of a monogenean parasite, Heterobothrium okamotoi.

The genetic mechanisms underlying host specificity of parasitic infections are largely unknown. After hatching, the larvae of the monogenean parasite, Heterobothrium okamotoi, attach to the gill filaments of hosts and the post-larval worms develop there by consuming nutrients from the host. The susceptibility to H. okamotoi infection differs markedly among fish species. While this parasite can grow on tiger pufferfish (also called fugu), Takifugu rubripes, it appears to be rejected by a close congener, grass pufferfish, Takifugu niphobles, after initial attachment to the gills. To determine the genetic architecture of the pufferfish responsible for this host specificity, we performed genome-wide quantitative trait loci analysis. We raised second generation (F2) hybrids of the two pufferfish species and experimentally infected them with the monogenean in vivo. To assess possible differences in host mechanisms between early and later periods of infection, we sampled fish three h and 21days after exposure. Genome scanning of fish from the 3h infection trial revealed suggestive quantitative trait loci on linkage groups 2 and 14, which affected the number of parasites on the gill. However, analysis of fish 21days p.i. detected a significant quantitative trait locus on linkage group 9 and three other suggestive quantitative trait loci on linkage groups 7, 18 and 22. These results indicated the polygenic nature of the host mechanisms involved in the infection/rejection of H. okamotoi. Moreover the analyses suggested that host factors may play a more important role during the growth period of the parasite than during initial host recognition at the time of attachment. Within the 95% confidence interval of the linkage group 9 quantitative trait locus in the fugu genome, there were 214 annotated protein-coding genes, including immunity-related genes such as Irak4, Muc2 and Muc5ac.