Two independent families with strongly suspected hereditary diffuse gastric cancer based on the probands' endoscopic findings.

Hereditary diffuse gastric cancer (HDGC) is the most famous of hereditary gastric cancer syndromes with an autosomal dominant inheritance pattern, and its diagnosis can be made by identifying a pathogenic germline variant in CDH1. We report two independent families that were strongly suspected of having HDGC based on endoscopic findings (multiple tiny, pale areas) obtained in the probands; the probands were pathologically diagnosed as having signet ring cell carcinoma (SRCC) and were genetically confirmed to have a pathogenic CDH1 germline variant. Although the updated International Gastric Cancer Linkage Consortium (IGCLC)'s clinical guidelines for HDGC (2015) state that screening/surveillance endoscopy should be performed (Cambridge protocol), the endoscopic findings obtained in the two presently reported families suggest that pale areas should be suspected as indicating the presence of SRCCs, and biopsies should be performed in addition to obtaining a precise family history in cases suspected of having HDGC.

Locally infiltrative inflammatory fibroid polyp of the ileum: report of a case showing transmural proliferation.

Morphologically, an inflammatory fibroid polyp (IFP) is usually centred in the submucosa. Extension of an IFP to the subserosa with destruction of the muscularis propria is exceedingly rare. Herein, we describe a 70-year-old woman who presented with right lower abdominal pain but was finally diagnosed with an IFP. Contrast-enhanced computed tomography revealed a target-like structure with a hypovascular mass at the leading edge, which was consistent with intussusception due to a tumour. Following surgery, the resected specimen displayed a mass measuring 4 × 3 × 3 cm that was protruding into the lumen. Microscopically, the mass was centred in the submucosa, extending up to the mucosal surface and down to the subserosa and serosa. The muscularis mucosae and muscularis propria were destroyed focally. A PDGFRA gene mutation in exon 2 (1837_1851 del) that was found in this case, as well as a highly infiltrative growth pattern, strongly supported the neoplastic nature of IFP.

HIF-1α, MDM2, CDK4, and p16 expression in ischemic fasciitis, focusing on its ischemic condition.

Ischemic fasciitis is a benign myofibroblastic lesion, occurring in the sacral region or proximal thigh of elderly or bedridden individuals. The pathogenesis of ischemic fasciitis is thought to be based on ischemic condition; however, it has never been demonstrated. In this study, we examined the expression of ischemia-associated proteins in ischemic fasciitis by immunohistochemical and genetic methods. Specifically, this study aimed to reveal the expression of HIF-1α, MDM2, CDK4, p16, and gene amplification of MDM2 gene. Seven cases of ischemic fasciitis from among the soft-tissue tumors registered at our institution were retrieved. Histopathological findings were as follows: poorly demarcated nodular masses, a proliferation of spindle-shaped fibroblastic or myofibroblastic cells with oval nuclei and eosinophilic or pale cytoplasm, zonal fibrinous deposition, pseudocystic degeneration, granulation-like proliferation of capillary vessels, ganglion-like cells, myxoid or hyalinized stroma, and chronic inflammatory infiltration. Immunohistochemically, the spindle cells were positive for HIF-1α (7/7 cases), MDM2 (4/7 cases), CDK4 (4/7 cases), p16 (7/7 cases), p53 (2/7 case), cyclin D1 (7/7 cases), and alpha-smooth muscle actin (6/7 cases). Neither MDM2 gene amplification nor USP6 gene split signal was detected in any case. Overexpression of the above proteins may be associated with the pathogenic mechanism of ischemic fasciitis. It is noted that the immunohistochemical positivity of MDM2, CDK4, and p16 do not necessarily indicate malignant neoplasm such as dedifferentiated liposarcoma.

Paratesticular dedifferentiated liposarcoma with prominent myxoid stroma: report of a case and review of the literature.

Paratesticular sarcoma is rare, but liposarcoma is its most common type. Paratesticular liposarcoma sometimes presents as dedifferentiated liposarcoma. Both high-grade and low-grade dedifferentiation have been reported. Herein, we presented a unique case of a 64-year-old man with low-grade dedifferentiated liposarcoma with prominent myxoid stroma. Well-differentiated liposarcoma components extended along the spermatic cord. The constituent cells of the dedifferentiated component were peculiar in that, they were relatively uniform cells with atypia and did not have pleomorphism to such an extent that it mimicked myxofibrosarcoma. This myxoid component was confidently differentiated from myxoid liposarcoma with the help of immunohistochemical analysis using CDK4 and MDM2. These two markers were also expressed in the well-differentiated component. It could therefore be confirmed that this sarcoma is dedifferentiated liposarcoma but is not mixed-type liposarcoma comprising well-differentiated liposarcoma and myxoid liposarcoma.

Germinoma with an extensive rhabdoid cell component centered at the corpus callosum.

Intracranial germinomas comprise 0.5-2.0 % of all central nervous system (CNS) tumors and 50-60 % of CNS germ cell tumors. They most frequently originate in the pineal gland and the suprasellar region. The corpus callosum is an extremely uncommon location for germinoma formation. Herein, we report about a 20-year-old man with a germinoma centered at the corpus callosum and that extended to both cerebral hemispheres. In addition to its location, this case is unique in that the amount of tumor cells with rhabdoid morphology exceeded that of tumor cells with typical morphology. The rhabdoid cell component showed an immunophenotype compatible with germinoma. While the presence of rhabdoid cells is generally regarded as a sign of aggressive behavior, the patient has been doing well for at least 4 years since undergoing radiation therapy and chemotherapy. The cellular composition of germinoma might not critically affect prognosis with adequate treatment.

A clear cell variant of mucoepidermoid carcinoma harboring CRTC1-MAML2 fusion gene found in buccal mucosa: report of a case showing a large clear cell component and lacking typical epidermoid cells and intermediate cells.

The predominance of clear cells in mucoepidermoid carcinomas (MEC) is rare, and cases in which this occurs are termed clear cell variants of MEC. We present a case of a 70-year-old woman complaining of a right buccal mucosal mass, which had increased in size over 1 year. Histological examination revealed the mass to be composed predominantly of clear tumor cells, with mucin-containing cells and intermediate cell-like cells. Immunohistochemistry indicated that the tumor was positive for CK5/6 and p63, but negative for myoepithelial markers such as S-100 protein, αSMA, and calponin. These findings ruled out the possibility of a clear cell myoepithelial carcinoma, which is the most frequently observed type of salivary carcinoma composed predominantly of clear cells. However, it is difficult to distinguish between clear cell variants of MEC and hyalinizing clear cell carcinoma. Therefore, we performed fluorescence in situ hybridization to determine whether MAML2 rearrangement had occurred in this mass. Direct sequencing of the RT-PCR product demonstrated CRTC1-MAML2 fusion between exon 1 of CRTC1 and exon 2 of MAML2. Thus, the diagnosis of clear cell variant of MEC was confirmed. This is the first report of CRTC1-MAML2 fusion gene detection in a clear cell variant of MEC.

Uroplakin II Expression in Breast Carcinomas Showing Apocrine Differentiation: Putting Some Emphasis on Invasive Pleomorphic Lobular Carcinoma as a Potential Mimic of Urothelial Carcinoma at Metastatic Sites.

Uroplakin II antibody is exclusively specific for urothelial carcinoma. Nonurothelial carcinoma has not been reported to be immunoreactive for uroplakin II. In the present study, we hypothesized that breast carcinoma showing apocrine differentiation, such as invasive pleomorphic lobular carcinoma (IPLC) and apocrine carcinoma (AC), stains positive for uroplakin II. We identified 6 cases of IPLC between 2000 and 2014 by searching a computerized pathological database. We randomly selected 10 cases of each classic invasive lobular carcinoma (cILC) and AC and five cases of apocrine metaplasia (AM) that coexisted in a surgically resected breast carcinoma specimen. Immunohistochemistry was performed for uroplakin II, GATA3, CK7, CK20, and other representative markers positive for urothelial carcinoma. All cases of IPLC, AC, and AM, except those of cILC, showed immunoreactivity for uroplakin II. Poorly differentiated urothelial carcinoma sometimes shows similar morphology to IPLC with the following immunophenotype: CK7+, CK20-, GATA3+, and uroplakin II+. In the present study, this immunophenotype was observed in all the cases of IPLC and AC. Therefore, when studying metastatic, poorly differentiated carcinoma showing the aforementioned immunophenotype, we should consider the possibility of it being IPLC in addition to metastatic urothelial carcinoma.

Pseudo-Meigs' syndrome secondary to metachronous ovarian metastases from transverse colon cancer.

Pseudo-Meigs' syndrome associated with colorectal cancer is extremely rare. We report here a case of pseudo-Meigs' syndrome secondary to metachronous ovarian metastases from colon cancer. A 65-year-old female with a history of surgery for transverse colon cancer and peritoneal dissemination suffered from metachronous ovarian metastases during treatment with systemic chemotherapy. At first, neither ascites nor pleural effusion was observed, but she later complained of progressive abdominal distention and dyspnea caused by rapidly increasing ascites and pleural effusion and rapidly enlarging ovarian metastases. Abdominocenteses were repeated, and cytological examinations of the fluids were all negative for malignant cells. We suspected pseudo-Meigs' syndrome, and bilateral oophorectomies were performed after thorough informed consent. The patient's postoperative condition improved rapidly after surgery. We conclude that pseudo-Meigs' syndrome should be included in the differential diagnosis of massive or rapidly increasing ascites and pleural effusion associated with large or rapidly enlarging ovarian tumors.

Neoadjuvant imatinib treatment and laparoscopic anus-preserving surgery for a large gastrointestinal stromal tumor of the rectum.

BACKGROUND: Resection of a gastrointestinal stromal tumor (GIST) of the rectum can be difficult because of the particular location in the pelvis, and a large rectal GIST often requires abdominoperineal resection. Recent reports demonstrate that neoadjuvant imatinib treatment improves surgical outcomes in patients with a rectal GIST, and there are only a few reports of the effectiveness of laparoscopic surgery for a rectal GIST. CASE PRESENTATION: A 46-year-old man was found to have a rectal GIST that measured 80 mm and was located on the anterior wall of the lower rectum. After 6 months treatment with imatinib, the tumor decreased in size to 37 mm, and laparoscopic low anterior resection was performed. The patient is currently alive without any evidence of recurrence 37 months after surgery. CONCLUSIONS: Neoadjuvant imatinib should be a treatment of choice for a large rectal GIST. When marked tumor shrinkage is achieved, laparoscopic surgery may be the preferred procedure.

Laparoscopic resection of adult colon duplication causing intussusception.

Gastrointestinal duplications are uncommon congenital malformations that can occur anywhere along the gastrointestinal tract. Most cases are recognized before the age of 2 years, and those encountered in adults are rare. We describe here a case of ascending colon duplication in a 20-year-old male that caused intussusception and was treated laparoscopically. Although computed tomography revealed a cystic mass filled with stool-like material, the preoperative diagnosis was a submucosal tumor of the ascending colon. We performed a laparoscopic right colectomy, and the postoperative pathological diagnosis was duplication of the ascending colon, both cystic and tubular components. We conclude that gastrointestinal duplications, although rare, should be considered in the differential diagnosis of all abdominal and submucosal cystic lesions and that laparoscopy is a preferred approach for the surgical treatment of gastrointestinal duplications.

E-cadherin-negative acinar cell carcinoma of the pancreas: report of a case showing a solid pseudopapillary growth pattern.

E-cadherin expression patterns in acinar cell carcinomas (ACCs) of the pancreas have not been well documented. Herein, we present a hitherto undescribed case of E-cadherin-negative ACC with a solid pseudopapillary growth pattern in a 65-year-old man. We used an antibody against the extracellular domain of E-cadherin. As a further unusual status in ACC, faint ß-catenin expression was observed in the cytoplasm of carcinoma cells. Morphological distinction from a solid pseudopapillary neoplasm (SPN) of the pancreas might be problematic in such a case, because of their similarities concerned with the growth pattern and E-cadherin negativity. Without nuclear accumulation of ß-catenin, a diagnosis of SPN was almost excluded. Immunoreactivity for trypsin and BCL10 made an accurate diagnosis of ACC to this case. The tumor recurred 10 months post-surgery as rapidly enlarging masses in the liver, presumably indicating the aggressiveness of the E-cadherin-negative phenotype among ACCs.

Breast carcinoma with a predominant duct-replacing component and chondroid matrix production.

Breast carcinomas that produce chondroid matrix are extremely rare. If the carcinoma is invasive, it is classified as a matrix-producing carcinoma (MPC). Herein, we present a case of a breast carcinoma, which showed duct-replacing growth with chondroid matrix production. A 63-year-old woman underwent fine needle aspiration cytology for suspected malignancy, based on radiological findings. Cellular components showed sufficient atypia to allow a diagnosis of malignancy. A partial mastectomy was performed, and no mass-forming lesion was apparent in the surgically resected specimen. Histopathological examination showed that the carcinoma produced chondroid matrix and grew replacing ducts, which were associated with a small amount of an obvious invasive component without matrix production. Some parts of the duct-replacing component might take the form of expansile invasion due to the absence of residual duct-lining myoepithelial cells; it is difficult to decide whether the duct-replacing component is invasive or not. However, regarding a few tumor nests, they would be recognized as MPC-like intraductal components because of the focal presence of myoepithelial cells around them. Hence, this carcinoma could not be definitely diagnosed as a MPC, even though we believe they are closely related. This is the first reported case of a breast carcinoma displaying duct-replacing growth with chondroid matrix production.

Methotrexate-associated lymphoproliferative disorder presenting as extranodal NK/T-cell lymphoma arising in the lungs.

Patients having rheumatoid arthritis (RA) treated with methotrexate (MTX) are at an increased risk of developing lymphoproliferative disorder (LPD). Epstein-Barr virus (EBV) sometimes contributes to the development of MTX-associated LPD. Herein, we report the case of a 64-year-old Japanese woman with RA who showed complications of EBV-positive MTX-associated LPD. This case is exceedingly rare in that the LPD was confined to the lungs and its subclassification was extranodal NK/T-cell lymphoma. Only four cases of extranodal NK/T-cell lymphoma in the setting of MTX-associated LPD have ever been reported in the English language literature, only one of which was an extranasal NK/T-cell lymphoma, similar to our case. Extranasal NK/T-cell lymphomas show more aggressive behavior than nasal NK/T-cell lymphomas, possibly reflected by the considerable re-exacerbation of the lesions in only two months after the cessation of MTX in our case. However, the SMILE regimen (steroid, methotrexate, ifosfamide, l-asparaginase, and etoposide) was able to suppress tumor growth in this case.

Two cases of matrix-producing carcinoma showing chondromyxoid matrix in cytological specimens.

Matrix-producing carcinoma (MPC) is extremely rare. Limited reports have described the cytological aspects of MPC. Herein, we present 2 cases of MPC, both of which showed ring-enhancement on magnetic resonance imaging (MRI) and chondromyxoid matrix on cytological specimens. In these cases, the diagnosis of MPC was preoperatively suspected. Recognizing extracellular matrix as chondromyxoid matrix on the cytological specimen is important in making a distinction between MPC and mucinous carcinoma. They share some features on cytology and MRI (ring-enhancement) but have different prognoses and involve different approaches for obtaining histological specimens for neoadjuvant therapy. The reason for the different approaches for obtaining the histological specimens is that tumor cells usually distribute peripherally in MPC in contrast to the relatively uniform distribution of mucinous carcinoma. Therefore, it would be helpful if the diagnosis of MPC can be suspected by examination of the cytological specimen.

Perivascular epithelioid cell tumor of the uterine cervix identified on a conventional cervical smear.

Perivascular epithelioid cell tumors (PEComas) most frequently involve the uterus, particularly the uterine corpus and very occasionally the cervix. One case of PEComa identified using a conventional cervical smear has previously been documented. Herein, we present the second such case. The patient was a 51-year-old woman with abnormal genital tract bleeding. Samples collected for conventional cervical smears were submitted for cytopathological examination, which revealed discohesive monotonous tumor cells showing epithelioid morphology, ample cytoplasm that was pale to weakly eosinophilic, and mildly enlarged nuclei. The cytopathological features were well correlated with histopathological findings. Upon immunohistochemistry, the tumor cells were positive for both melanocytic and smooth muscle markers. Based on these findings, PEComa was diagnosed. Subsequently, a total hysterectomy with bilateral salpingo-oophorectomy was performed, revealing that the tumor (28 × 22 × 12 mm) was located at the superficial part of the endocervix. We propose that the cytopathological findings described herein can guide the diagnosis of PEComa, even though this tumor is rare.

Transition between morule-like and solid components may occur in solid-predominant adenocarcinoma of the lung: report of 2 cases with EGFR and KRAS mutations.

A limited number of pulmonary adenocarcinoma cases with morule-like components have been described to date, and the most frequent histological subtype is papillary-predominant adenocarcinoma. Occasionally, this type of adenocarcinoma is associated with solid-predominant adenocarcinoma. EGFR mutations are predominant in adenocarcinoma with morule-like components, followed by ALK rearrangements. Herein, we present 2 cases of solid-predominant adenocarcinoma with morule-like components harboring either an EGFR or KRAS mutation. This KRAS-mutant case is the first to be associated with morule-like components, to the best of our knowledge. Both cases showed transition between micropapillary and morule-like components. Transition between morule-like and solid components was also observed in both cases. Although a few cases of solid-predominant adenocarcinoma have been shown to harbor morule-like components, this type of transition has not been previously well described. We surmised that the solid components of some EGFR-mutant adenocarcinomas might be derived from morule-like components.

Granulomatous inflammation of pulmonary squamous cell carcinoma: a rare phenomenon.

Some neoplasms are associated with granulomatous inflammation. Granuloma formation in tumor tissue is caused by the cytokines derived from either the main tumor or other cells surrounding the tumor. In other instances, granulomatous inflammation is observed in the lymph nodes draining a tumor. This has been recognized as a sarcoid-like reaction. Herein, we report of a 75-year-old man with pulmonary squamous cell carcinoma (SCC), where granulomatous inflammation was observed extensively at the primary site. The carcinoma seemed to partly regress. In the regressing area, tumor cell debris was surrounded by granuloma. In contrast, no granuloma was identified in the dissected regional lymph nodes. To the best of our knowledge, such a case of SCC had not been described thus far. More case studies are required to determine whether tumor-related granuloma is the main cause of regression or whether it is just a secondary phenomenon caused by the attack and destruction of the tumor by lymphocytes.

A neurogenic tumor containing a low-grade malignant peripheral nerve sheath tumor (MPNST) component with loss of p16 expression and homozygous deletion of CDKN2A/p16: a case report showing progression from a neurofibroma to a high-grade MPNST.

Development of malignant peripheral nerve sheath tumors (MPNSTs) is a stepwise process that involves the alteration of many cell cycle regulators and the double inactivation of the NF1 gene. Inactivation of the TP53 gene and deletion of the CDKN2A/p16 gene are known to play an important role in the process. Herein, we present a 19-year-old man with a familial history of neurofibromatosis type 1, in whom the tumor arose from the intercostal nerve and showed 3 components: a neurofibroma, a low-grade MPNST, and a high-grade MPNST. Loss of p16 expression and homozygous deletion of the CDKN2A/p16 gene were observed in both the low-grade and the high-grade MPNST. In contrast to low-grade MPNSTs, high-grade MPNSTs generally tend to lose expression of p16 and harbor homozygous deletion of the CDKN2A/p16 gene. Loss of p16 expression and homozygous deletion of the CDKN2A/p16 gene in low-grade MPNST in our case might be related to its progression to high-grade MPNST. To the best of our knowledge, this is the first study correlating the p16 expression status and CDKN2A/p16 gene alteration in low-grade MPNSTs.

Myxoid epithelioid gastrointestinal stromal tumor harboring an unreported PDGFRA mutation: report of a case and review of the literature.

Activating mutations of platelet-derived growth factor receptor α (PDGFRA) are detected in a significant proportion of gastrointestinal stromal tumors (GISTs), in addition to the more frequent mutation in c-kit. GISTs with PDGFRA mutations have been found to have several characteristic morphological features, sometimes allowing to discriminate them from GISTs with c-kit mutations. Among these, epithelioid morphology in tumor cells and tumor-infiltrating mast cells are powerful predictors of PDGFRA mutations. Although myxoid stroma by itself is not so much a reliable predictor of PDGFRA mutation, myxoid stroma in conjunction with epithelioid morphology in tumor cells is a powerful predictor of mutations in this gene. GISTs showing either weak or negative immunoreactivity for c-kit and epithelioid cells with myxoid stroma are called myxoid epithelioid GISTs, which typically show PDGFRA mutation. Herein, we presented a case of a 59-year-old woman with myxoid epithelioid GIST of the stomach. A unique finding in this case was eosinophil infiltration, probably more numerous than mast cells; mast cell infiltration is known to be usually found in myxoid epithelioid GIST. The existence of a similar mechanism in eosinophil and mast cell recruitment via tumor-producing stem cell factor is speculated. Mutational analyses revealed a PDGFRA exon 18 mutation: D842_H845del, D846N. Combined deletion and substitution mutation has been reported in rare instances, but to the best of our knowledge, D846N has not been documented.

Adenoid cystic carcinoma of the right main bronchus showing squamous differentiation and mimicking mucoepidermoid carcinoma: a case report.

Complete dissection of tracheobronchial adenoid cystic carcinoma (TACC) by surgery alone is sometimes difficult and has a greater propensity than tracheobronchial mucoepidermoid carcinoma (TMEC) for its surgical margin to become positive. In addition, TACC is more likely to present distant metastases than TMEC. Considering these facts, TACC and TMEC should be differentiated based on histopathological examination of biopsy specimens. Herein, we present a case of 54-year-old woman with a tumor in the right main bronchus, whose biopsy specimen was difficult to diagnose as TACC or TMEC. The specimen from the rounded protrusion of the tumor showed squamous differentiation, along with the presence of glandular and basaloid cells, making morphological examination alone ineffective in rendering a definite diagnosis. Thus, the addition of immunohistochemical analysis, αSMA and CD43 expression in basaloid cells and c-kit expression in glandular cells, was useful for accurately diagnosing TACC in this case. The squamous component was considered to be neoplastic because of its increased expression of cyclin D1 and overexpression of p16. The surgically resected specimen contained typical morphology of ACC, and the diagnosis of TACC was definitely confirmed.