[Multiple myeloma with myelofibrosis at diagnosis and aggressive extramedullary relapse after autologous stem cell transplantation].

A 66-year-old man was diagnosed with symptomatic IgG-λ multiple myeloma based on the presence of anemia, thrombocytopenia, renal dysfunction, and a tumor on the right sixth rib. Bone marrow aspiration yielded a dry tap and biopsy revealed myelofibrosis grade 2. Partial response was achieved with Bd (bortezomib and dexamethasone) and VRd (bortezomib, lenalidomide, and dexamethasone). The patient received autologous stem cell transplantation, but the myeloma relapsed 3 months later, and liver tumors developed as well. DKd (daratumumab, carfilzomib, and dexamethasone) was administered, but the patient died due to disease progression. Autopsy revealed multiple extramedullary lesions in the liver, spleen, gallbladder, adrenal glands, kidneys, and multiple lymph nodes, as well as ascites.

[Plasmablastic lymphoma presenting with plasmacytosis and polyclonal hypergammopathy].

A 72-year-old woman presented with generalized lymphadenopathies and plasmacytosis accompanied by polyclonal hypergammopathy. 18F-fluorodeoxyglucose positron emission tomography (FDG-PET) showed FDG accumulation in the systemic lymph nodes, spleen, and multiple bones. Human immunodeficiency virus antibody was negative. Lymph node histologic findings showed a monotonous population of plasma cells with a starry-sky appearance. The cells were positive for CD19, λ, and Epstein-Barr virus-encoded RNA, and negative for CD20 and CD56. The MIB-1 index was 80%. A diagnosis of plasmablastic lymphoma with plasmacytosis and polyclonal hypergammopathy was made, and complete metabolic response was achieved after six cycles of dose-adjusted-EPOCH therapy (etoposide, prednisolone, vincristine, cyclophosphamide, and doxorubicin).

[Busulfan/thiotepa followed by autologous peripheral blood stem cell transplantation for refractory diffuse large B-cell lymphoma accompanied by hypopyon].

A 54-year-old male patient, who presented with multiple lymphadenopathies, bilateral leg edema, and oscheohydrocele, was diagnosed with diffuse large B-cell lymphoma (DLBCL) stage IVB. His lymphadenopathies disappeared after six courses of R-CHOP therapy, which consist of rituximab, cyclophosphamide, doxorubicin, vincristine, and prednisolone); however, right hypopyon and partly remaining testicular soft tissue masses with fluorodeoxyglucose accumulation were observed. Lymphoma cell infiltration was observed in the aqueous humor of the right anterior chamber and testis, which indicates DLBCL progression. Hypopyon disappeared after the first course of intrathecal chemotherapy combined with R-HDMA therapy, which consists of rituximab and high-dose methotrexate/cytarabine, but recurred in the third course. The patient then underwent busulfan and thiotepa (BuTT) therapy followed by autologous peripheral blood stem cell transplantation (auto-PBSCT) after four courses of R-HDMA therapy. Hypopyon promptly disappeared after BuTT therapy and no hypopyon recurrence was observed 9 months after auto-PBSCT. Therefore, BuTT therapy is effective for hypopyon associated with refractory DLBCL.

[Successful treatment of HHV8-negative effusion-based lymphoma with drainage of pleural effusion].

Two cases of human herpesvirus 8 (HHV8)-negative effusion-based lymphoma (EBL) involving unilateral pleural effusion that regressed only after drainage are reported. Cases 1 and 2 were 91- and 81-year-old men with right and left pleural effusion, respectively. No chemotherapy was administered to either patient because of their advanced age and the presence of cardiac comorbidities. They completely recovered after effusion drainage alone without relapse till the last observation. Thus, this study suggests that some patients with HHV8-negative EBL can be safely managed with effusion drainage alone.

A single-arm, phase 2 study of adjuvant chemotherapy with oral tegafur-uracil for pathologically lymphovascular invasion positive stage IA non-small cell lung cancer: LOGIK0602 study.

BACKGROUND: Lymphovascular invasion (LVI), which includes vascular or lymphatic invasions, is a representative prognostic factor even in patients with resected stage IA non-small cell lung cancer (NSCLC). Because tegafur-uracil is effective on cancers with LVI, we conducted a multi-center single-arm phase II study to estimate the efficacy of adjuvant tegafur-uracil in patients with LVI-positive stage IA NSCLC. METHODS: Patients with completely resected LVI-positive stage IA NSCLC were registered. LVI was diagnosed by consensus of two of three pathologists. Adjuvant chemotherapy consisted of 2 years of oral tegafur-uracil at 250 mg/m2/day. Fifty-five patients from 7 institutions were enrolled from June 2007 to September 2012. RESULTS: Among the 52 eligible patients, 36 (69.2%) completed the treatment course. There were 39 male and 13 female patients. The observation period was calculated as 562 to 3107 days using the reverse Kaplan-Meier method. The 5-year overall and relapse free survival rates were 94.2 and 88.5% respectively, which were significantly better than that of any other studies conducted on patients with LVI-positive stage IA NSCLC. Notably, the overall survival rate was 15% better than that of our prior retrospective study. The retrospective analysis of stage IA NSCLC patients who had received an operation in the same period revealed that the 5-year overall survival rate of the LVI positive group was 73.6% when adjuvant chemotherapy was not applied. Among 55 safety analysis sets, 4 cases of grade 3 hepatic function disorder (9.1%) and 5 cases of grade 2 anorexia (10.9%) were most frequently observed. No grade 4 adverse effects were encountered. CONCLUSION: A 2-year course of oral tegafur-uracil administration is feasible and might have a significant benefit in the adjuvant treatment of LVI-positive stage IA NSCLC. TRIAL REGISTRATION: UMIN identifier: UMIN000005921 ; Date of enrolment of the first participant to the trial: 19 June 2007; Date of registration: 5 July 2011 (retrospectively registered).

Immunohistochemical Reactivity of Prostate-Specific Markers for Salivary Duct Carcinoma.

OBJECTIVES: NKX3.1, a transcription factor related to androgen expression, has recently been introduced as a diagnostic marker of prostate adenocarcinoma. Salivary duct carcinoma (SDC) is typically positive for androgen receptor (AR). Therefore, we hypothesized that NKX3.1 is a new immunohistochemical marker for SDC and aimed to investigate whether NKX3.1 staining in combination with other immunomarkers of prostate carcinoma could have a diagnostic or prognostic value in SDC. METHODS: Materials obtained from 42 resected SDCs were examined by immunohistochemistry using antibodies against AR, NKX3.1, α-methylacyl-CoA racemase (AMACR), prostatic acid phosphatase (PAP), and prostate-specific antigen (PSA). RESULTS: In immunoreactivity among SDC cases, 81.0, 35.7, 58.5, 33.3, and 0% were positive for AR, NKX3.1, AMACR, PAP, and PSA, respectively. AMACR and PAP immunoreactivity rates were higher in recurrence cases than in cases with no recurrence. CONCLUSIONS: NKX3.1 expression is useful for SDC diagnosis, but decreased NKX3.1 expression was not correlated with SDC progression. The immunoreactivity of AMACR and PAP could be useful for assessing prognosis in SDC, but immunohistochemical staining of prostate-specific markers should be interpreted with caution when determining whether a metastatic tumor is of prostate origin, especially when patients have a history of SDC.

Myopathy in a patient with systemic AA amyloidosis possibly induced by psoriasis vulgaris: An autopsy case.

INTRODUCTION: Amyloid myopathy is a rare manifestation of primary systemic amyloid light-chain (AL) amyloidosis, but it has not been reported to occur in secondary amyloid A (AA) amyloidosis. METHODS: We describe a 46-year-old man with psoriasis vulgaris who presented with idiopathic upper and lower limb weakness and was eventually diagnosed with hypertrophic cardiomyopathy. Muscle biopsy findings were compatible with mild inflammatory myopathy. He died of cardiopulmonary arrest, and an autopsy was performed. RESULTS: The autopsy revealed amyloid plaques immunopositive for AA (but not AL or transthyretin) in the perimysial, perivascular, and endomysial regions of the iliopsoas muscle. The final diagnosis was systemic AA amyloidosis with muscle amyloid angiopathy, possibly induced by psoriasis vulgaris. CONCLUSION: This is an extremely rare autopsy case of myopathy in a patient with systemic AA amyloidosis. The reason for the unusually large amount of amyloid deposition in muscle blood vessel walls remains unclear.

KIT (CD117) Expression in Benign and Malignant Sweat Gland Tumors.

KIT (CD117, c-kit) is a receptor tyrosine kinase involved in the tumorigenesis of several neoplasms. KIT is expressed by the secretory cells of normal sweat glands. We studied the KIT expression and KIT mutational status in various benign and malignant tumors of eccrine and apocrine glands. We included a total of 108 cases comprising 10 benign and 6 malignant sweat gland tumors, and KIT expression was immunohistochemically detected (positive rate): 10 syringomas (0%), 8 poromas (25%), 20 mixed tumors (40%), 21 spiradenomas (43%), 1 cylindroma (0%), 5 hidradenomas (40%), 7 syringocystadenoma papilliferum cases (0%), 1 papillary hidradenoma (100%), 2 tubulopapillary hidradenomas (50%), 8 hidrocystomas (29%), 2 adenoid cystic carcinomas (100%), 5 porocarcinomas (20%), 6 apocrine carcinomas (33%), 10 extramammary Paget diseases (30%), 1 spiradenocarcinoma (100%), and 1 syringocystadenocarcinoma papilliferum (0%). Most KIT-positive cells were luminal cells, arising from glandular structures. We performed polymerase chain reaction-single-strand conformation polymorphism for detecting KIT mutational status. All cases showed no mutations at hot spots for KIT (exons 9, 11, 13, and 17). KIT mutation does not seem to be mechanism for KIT expression, but the expression may be from native sweat glands.

[Successful treatment with high-dose methotrexate/cytarabine regimen in a patient in SMILE regimen-resistant extranodal natural killer/T-cell lymphoma].

A 28-year-old man complained of pain in the oral mucosa and pharynx in March 2011, and then developed fever and generalized swelling of the cheek. In March 2012, a gum biopsy led to a diagnosis of extranodal natural killer/T-cell lymphoma (ENKL). (18)F-FDG-PET revealed significant uptake in the mouth, tonsils, jawbone, shoulder blade, humerus, ilium, femur, and spleen. After two courses of the SMILE (dexamethasone, methotrexate (MTX), ifosfamide, L-asparaginase, etoposide) regimen, the response was stable disease. However, a high-dose MTX/cytarabine (MA) regimen was effective. After three courses of the MA regimen, a partial response was achieved. Then, allogeneic bone marrow transplantation from an unrelated donor was performed. At 10 months after transplantation, there was no sign of recurrence. Although the optimal treatment for ENKL refractory to the SMILE regimen has yet to be established, our case suggests the MA regimen to be a potentially effective treatment option.

Ectopic pancreatic adenocarcinoma in Meckel's diverticulum: a case report.

BACKGROUND: Malignant neoplasms arising from Meckel's diverticulum are rare and an adenocarcinoma in Meckel's diverticulum originating from ectopic pancreatic tissue is even rarer. Herein, we report a patient with an ectopic pancreatic adenocarcinoma in Meckel's diverticulum who was successfully treated with surgery and chemotherapy. CASE PRESENTATION: A woman in her sixties presented to another hospital with abdominal pain. Plain computed tomography suggested an abdominal tumor and she was referred to our hospital. Enhanced computed tomography revealed a 23-mm low-density tumor in the abdominal cavity. Surgery was performed with a tentative diagnosis of a mesenteric tumor, such as a gastrointestinal stromal tumor, schwannoma, or lymphoma. First, we inspected the peritoneal cavity with a laparoscope. This revealed numerous nodules in the small bowel mesentery, suggesting peritoneal dissemination. A 20-mm-diameter white tumor was found in the small intestine and diagnosed as a small intestinal cancer. The small intestine was partially resected laparoscopically through a small skin incision. The patient's postoperative course was uneventful, and she was discharged on postoperative day 9. Pathological examination revealed well-differentiated adenocarcinoma in the small intestine. The tumor had developed from a sac-like portion protruding toward the serosal side and had a glandular structure lined with flattened atypical cells. Neither pancreatic acinar cells nor islets of Langerhans were evident, suggesting a Heinrich type 3 ectopic pancreas. The final diagnosis was an adenocarcinoma originating from an ectopic pancreas in Meckel's diverticulum. After a smooth recovery, the patient commenced chemotherapy for pancreatic cancer. CONCLUSIONS: We present a very rare case of ectopic pancreatic carcinoma in Meckel's diverticulum.

Giant gallbladder cyst with acute cholecystitis: a case report.

BACKGROUND: Gallbladder cysts are rare diseases with very few reported cases, and no clinical or histological definition has been established. Furthermore, cases of giant cysts outside the gallbladder wall are extremely rare. We report a rare case of giant gallbladder cyst with acute cholecystitis. CASE PRESENTATION: An 85-year-old woman with appetite loss and right lower abdominal pain lasting 2 days presented to our hospital. At first, the patient's abdominal pain was mild to moderate with no fever. Blood tests revealed a white blood cell count of 10,950/mm3, and the C-reactive protein (CRP) level was 14.35 mg/dl. A contrast-enhanced computed tomography (CT) scan of the abdomen revealed a grossly distended gallbladder (14.5 × 14.5 × 8.7 cm) with an incarcerated stone in the cystic duct. The patient was treated by percutaneous transhepatic gallbladder drainage (PTGBD) with 735 ml of drainage fluid. Oral contrast magnetic resonance cholangiopancreatography (MRCP) revealed that gallbladder swelling remained (14.0 × 6.5 cm) 3 days after PTGBD. We performed laparoscopic cholecystectomy 6 days after PTGBD. Because of the severe adhesion around the junction of the cystic and common bile ducts, we performed open cholecystectomy. The resected specimen was 14 × 11 cm in size and consisted of a gallbladder (6 × 7 cm) with a stone (2.4 × 1.8 cm) in the gallbladder and a large cystic lesion (18 × 18 cm) outside the gallbladder wall. The cystic lesion had a wall thickness of 6 to 12 mm and internal septal structures and contained hemorrhagic and necrotic tissue. Histological examination revealed that the specimens showed a mildly swollen gallbladder and a cystic lesion on the outside of the gallbladder wall, adjacent to the gallbladder wall, with wall thickening and inflammation. The cystic lesion suggested gallbladder duplication, gallbladder diverticulum or extension of the Rokitansky-Aschoff sinus (RAS). There was no malignancy. The patient's postoperative course was uneventful, and she was discharged 5 days after the operation. CONCLUSION: We present a very rare case of giant gallbladder cyst with acute cholecystitis revealed by cholecystectomy.

Gilteritinib as Bridging and Posttransplant Maintenance for Relapsed Acute Myeloid Leukemia with FLT3-ITD Mutation Accompanied by Extramedullary Disease in Elderly.

A 69-year-old woman was diagnosed with acute myeloid leukemia (AML) with an FMS-like tyrosine kinase 3-internal tandem duplication (FLT3-ITD) mutation. Complete remission (CR) was achieved after induction therapy, but AML resulted in a hematological relapse two months after the consolidation chemotherapy. Relapse was accompanied by multiple skin lesions that demonstrated leukemic cell infiltration as well as a drooping right eyelid with extroversion of the eye due to right oculomotor palsy. Gilteritinib was started as salvage therapy, and bone marrow blasts decreased to 0.8% after one month. Two months later, the eye symptoms improved, and the patient underwent cord blood transplantation (CBT). The skin lesions disappeared after the conditioning regimen, and the patient achieved CR status with complete donor chimerism at day 28. Gilteritinib was restarted as posttransplant maintenance therapy on day 53 of CBT. No adverse events other than mild hepatotoxicity were observed, and the patient was alive and in CR status, while continuing gilteritinib at one year and seven months after CBT. Bridging and posttransplant maintenance therapy with gilteritinib may be a promising therapeutic option for relapsed AML with the FLT3-ITD mutation in elderly patients.

Liposarcoma of the pleural cavity.

Liposarcoma rarely occurs in the pleura or thoracic cavity, and few reports appear in the literature. We hypothesized that combining clinicopathologic, immunohistochemical, and fluorescence in situ hybridization methods would allow definite diagnoses. Using formalin-fixed, paraffin-embedded blocks, we examined 6 atypical lipomatous tumor/well-differentiated liposarcomas (ALT/WDLPS), 5 dedifferentiated liposarcomas (DDLPSs), 2 pleomorphic liposarcomas, and 1 myxoid liposarcoma (MLPS). We used the Kaplan-Meier method and the Wilcoxon test for survival analysis for prognostic factor evaluation. Histologically, ALT/WDLPS was composed of a relatively mature adipocytic proliferation, accompanied by some lipoblasts. DDLPS exhibited round-to-oval tumor cells with a high nucleus-to-cytoplasm ratio that had proliferated in nests, accompanied in case 10 by some giant cells but no fatty cells. The pleomorphic type contained a varying proportion of pleomorphic lipoblasts. MLPS displayed uniform round- to oval-shaped cells and small signet-ring lipoblasts in a myxoid stroma. Immunohistochemically, 11 (79%), 11 (79%), and 10 (71%) of 14 cases were positive for S-100, p16, and CDK4, respectively. Six of the 14 cases (43%) were positive for MDM2 and adipophilin. One case of ALT/WDLPS and 3 cases of DDLPS exhibited MDM2 amplification by fluorescence in situ hybridization (Vysis LSI MDM2 SpectrumGreen Probe plus Vysis CEP 12 SpectrumOrange probe). ALT/WDLPS was the most favorable type for survival, while adipophilin tended to be a negative prognostic factor for pleural liposarcoma. For a firm diagnosis of liposarcoma in the pleura, immunohistochemistry for CDK4, MDM2, and adipophilin together with MDM2 gene amplification by fluorescence in situ hybridization may be an important diagnostic tool.

Successful treatment with tirabrutinib for relapsed lymphoplasmacytic lymphoma complicated by Bing-Neel syndrome.

A 53-year-old woman was diagnosed with lymphoplasmacytic lymphoma (LPL)/Waldenström's macroglobulinemia (WM) in 2008. Six courses of R-COP (rituximab, cyclophosphamide, vincristine, and prednisolone) resulted in complete remission, but LPL/WM relapsed in 2015. After six courses of R-CHOP (rituximab, cyclophosphamide, doxorubicin, vincristine, prednisolone), the M-peak disappeared, but the patient presented with muscle weakness and sensory disturbance in the lower extremities. No lesions were apparent in the brain parenchyma, but T2-weighted magnetic resonance imaging (MRI) showed a signal-hyperintense area with contrast enhancement in the spinal cord at the C2-4 and Th2-3 levels, and cerebrospinal fluid (CSF) examination showed only a few mononuclear cells. In 2020, the patient started to require walking assistance, and MRI findings worsened. Neurologically, lower limb muscle strength was reduced (manual muscle test score 3), and sensations of touch and pain were about 30% of normal. Vibratory sensation was absent at the knees and medial malleoli, accompanied by dysuria due to neurogenic bladder. CSF cell count was 15/µl (all mononuclear cells). Bing-Neel syndrome (BNS) was diagnosed and tirabrutinib was started. Within 2 months of treatment, lower extremity muscle strength had normalized and MRI findings had improved. Tirabrutinib may offer a promising therapeutic option for BNS.

Successful treatment with tirabrutinib for relapsed Bing-Neel syndrome following high-dose methotrexate and craniospinal irradiation.

A 63-year-old man was diagnosed with Waldenström's macroglobulinemia (WM). Six courses of R-CHOP (rituximab, cyclophosphamide, doxorubicin, vincristine, and prednisolone) resulted in complete remission, but WM relapsed three years after R-CHOP. After six courses of BR (bendamustine, rituximab), the serum IgM level and CRP normalized. Four years after BR, the patient presented with muscle weakness, sensory disturbance, and myoclonus of lower limbs. T2-weighted magnetic resonance imaging (MRI) showed areas of signal hyperintensity with contrast enhancement in the right temporal and parietal lobes in brain parenchyma, medulla, bilateral basal ganglia, white matter of occipital lobe, and thoracic spinal cord at the Th2-11 levels. Open brain biopsy revealed diffuse proliferation of small lymphocytes and plasmacytoid lymphocytes on the brain surface and around cerebral blood vessels, resulting in a diagnosis of Bing-Neel syndrome (BNS). Two courses of R-MPV (rituximab, methotrexate, procarbazine, and vincristine) resulted in progressive disease, but the neurological symptoms and MRI findings improved following craniospinal irradiation of 30.6 Gy. Three years after craniospinal irradiation, T2-weighted MRI showed recurrence of BNS with progression of myoclonus of lower limbs and IgM elevation. Tirabrutinib was started for the second recurrence of WM and progression of BNS. Two months after the initiation of treatment with tirabrutinib, the myoclonus of lower limbs disappeared and the MRI findings showed improvement. Serum IgM levels decreased and no adverse events were observed. Tirabrutinib shows promise as a therapeutic option for relapsed BNS.

Pathological and immunohistological findings and genetic aberrations of intestinal enteropathy-associated T cell lymphoma in Japan.

AIMS: To elucidate the clinicopathological findings of primary intestinal enteropathy-associated T cell lymphoma (EATL) in Japan, a non-endemic area for coeliac disease. METHODS AND RESULTS: Of the 24 cases, four (17%) had large-cell lymphoma (type I), and the remaining 20 (83%) had medium-sized lymphoma (type II). Lymphoma cells of the three type I cases were CD56-positive. Only one (4%) case showed typical CD56- and CD8-negative and CD30-positive type I EATL. In type II EATL, lymphoma cells of the 16 (80%) and 11 (55%) cases were positive for CD56 and CD8, respectively. Intramucosal tumour spreading and adjacent enteropathy-like lesions were detected in 15 (71%) and 16 (76%) of 21 cases, with a severe increase of intraepithelial lymphocytes (IELs) in 12 (57%). IELs of enteropathy-like lesions in five (24%) cases expressed T-bet, with no cases of CD30-positive IELs. Characteristic findings from comparative genomic hybridization of 15 cases indicated gains of 8q2 (47%), Xp (53%) and Xq (73%), but no gain of 9q3. Regarding, human leucocyte antigen (HLA) status, six cases examined did not express the DQB1*02 allele. CONCLUSIONS: Japanese EATL exhibited different histology, cytogenetic findings and HLA status from those of typical type I EATL. The rare incidence of coeliac disease may influence the tumour cell characteristics of EATL and IELs.

Pregnancy-unrelated spontaneous rupture of a right ovarian artery aneurysm.

Spontaneous rupture of an ovarian artery aneurysm is extremely rare. It can lead to retroperitoneal hemorrhage that is often life-threatening. We report a case of pregnancy-unrelated spontaneous rupture of a right ovarian artery aneurysm in a multiparous woman. A 29-year-old woman, gravida 3, para 3, whose latest pregnancy involved uneventful gestation and delivery 2 years previously, was admitted for right flank pain. The urine test result for pregnancy was negative. Computed tomography revealed a large retroperitoneal hematoma and right ovarian artery aneurysm with contrast extravasation. After selective angiography, embolization of the right ovarian artery was successfully achieved using microcoils. Diagnostic angiography with subsequent transcatheter arterial embolization is an effective and less invasive technique for the management of ovarian artery aneurysm.

Lymphoepithelioma-like carcinoma of the uterine cervix.

PURPOSE: To elucidate the clinicopathologic features of lymphoepithelioma-like carcinoma (LELC) of the uterine cervix, we examined three Japanese cases. METHODS: We collected three cases of LELC of the uterine cervix between 2000 and 2007. We examined these patients' clinicopathologic data, Epstein-Barr virus (EBV) and human papilloma virus (HPV) infectious status, and infiltrated lymphocyte population. RESULTS: Our patients had disease Fédération Internatinale de Gynécologie et d'Obstétrique stages I and II. All of them were free of disease at the time of the study. Macroscopically, one of the three tumors was polypoid. All tumor cells were negative for EBV and HPV using in situ hybridization and immunohistochemistry. The inflammatory background contained many CD3(+) and CD8(+) cells, but there were few CD4(+), CD20(+), or CD79a(+) cells. CONCLUSIONS: In our Japanese series, LELC of the uterine cervix showed good prognosis, and there is no relationship between this carcinoma and EBV or HPV infection.

Clinicopathologic study of deciduoid mesothelioma using SMARCB1/INI1 immunohistochemistry and fluorescence in situ hybridization.

Deciduoid mesothelioma is a rare variant of epithelioid mesothelioma. Malignant rhabdoid tumors, renal medullary carcinoma, and some synovial sarcomas show a loss of SMARCB1/INI1 protein, a member of the SWI/SNF chromatin-remodeling complex. All of those tumors are known to have rhabdoid cells. Some mesothelioma cases, such as those of the deciduoid type, have also been reported to possess such rhabdoid features. Since this topic has not been studied in malignant mesothelioma, we analyzed the immunohistochemical expression of SMARCB1/INI1 in malignant mesotheliomas [45 epithelioid type (including 9 deciduoid type), 12 biphasic type, and 17 sarcomatoid type]. We employed (a) SMARCB1/INI1 immunohistochemistry, using an antibody to the INI1 gene product and (b) Fisher exact test, logistic regression analysis, the Kaplan-Meier method, and the Wilcoxon test for survival analysis for prognostic factor evaluation (SAS 9.4; SAS Institute, Cary, NC). The results showed that 17 of 74 (23%) malignant mesothelioma cases (epithelioid: 24%; biphasic; 8%; sarcomatoid; 29%) had reduced SMARCB1/INI1 expression. Reduced SMARCB1/INI1 expression appeared to be more frequent in the deciduoid type (67%), of which there were admittedly only a few cases, than in either the epithelioid type (14%) or biphasic type (8%), whether or not rhabdoid cells were present, but not different between the deciduoid and sarcomatoid types. However, there was no statistically significant difference in prognosis between malignant mesotheliomas with reduced versus preserved SMARCB1/INI1 protein expression. The results suggest that in differential diagnosis, cases with reduced SMARCB1/INI1 protein expression should not be excluded from a diagnosis of malignant mesothelioma.

Colon adenoma and adenocarcinoma with clear cell components - two case reports.

BACKGROUND: Diagnoses reflect clear cell morphologies when tumor cells have clear cytoplasm in many organs, and the nature of such clear cells is typically identified. Colorectal tubular adenoma or adenocarcinoma, conversely, rarely show clear cells, the reason for which remains uncertain. We report 2 colon tumors with clear cell components (Case 1: adenoma; Case 2: adenocarcinoma) and investigate the nature of the clear cells. CASE PRESENTATION: Case 1 was a 75-year-old man with a superficial elevated polyp detected in the rectum for whom endoscopic submucosal dissection was performed. Microscopically, 10% of the tumor showed dysplastic columnar epithelium with clear cytoplasm forming tubular structures accompanied by conventional tubular adenoma. Case 2 was a 58-year-old man with a pedunculated polyp found in his sigmoid colon for which polypectomy was performed. Microscopically, 90% of the tumor showed dysplastic columnar epithelium with clear cytoplasm forming fused glands or cribriform structures adjacent to the ordinal tubular adenocarcinoma. In both cases, clear and ordinary tumor cells were negative for CK7 and positive for CK20 and CDX2, consistent with findings of colorectal origin. Different results were found for CEA and CD10 staining. CEA was positive on the luminal side of the conventional area in contrast diffuse cytoplasmic staining of the clear cell area in both cases. CD10 was only positive for the clear cell component of case 2. The clear cell components were negative for Periodic acid-Schiff (PAS), Alcian blue, and mucicarmine staining and AFP immunohistochemistry. An ultrastructural examination found multiple cytoplasmic lipid-like vacuoles in the clear cell component that were predominantly negative for adipophilin by immunoelectron microscopy. CONCLUSIONS: We investigated tubular adenoma and tubular adenocarcinoma with clear cell components. The accompanying conventional tubular adenoma or adenocarcinoma cells helped us to evaluate the atypia of the clear cells. Diffuse cytoplasmic staining of CEA and CD10 suggested that the clear cell component might harbor malignant potential. We were unable to verify the well-known causes of clear cytoplasm, such as an accumulation of glycogen, lipid, or mucin and enteroblastic differentiation. The causes of clear cells in the colorectal region remain uncertain; however, possible explanations include autolysis and carbohydrate elution.