The aryl hydrocarbon receptor instructs the immunomodulatory profile of a subset of Clec4a4+ eosinophils unique to the small intestine.

C-type lectin domain family 4, member a4 (Clec4a4) is a C-type lectin inhibitory receptor specific for glycans thought to be exclusively expressed on murine CD8α− conventional dendritic cells. Using newly generated Clec4a4-mCherry knock-in mice, we identify a subset of Clec4a4-expressing eosinophils uniquely localized in the small intestine lamina propria. Clec4a4+ eosinophils evinced an immunomodulatory signature, whereas Clec4a4− eosinophils manifested a proinflammatory profile. Clec4a4+ eosinophils expressed high levels of aryl hydrocarbon receptor (Ahr), which drove the expression of Clec4a4 as well as other immunomodulatory features, such as PD-L1. The abundance of Clec4a4+ eosinophils was dependent on dietary AHR ligands, increased with aging, and declined in inflammatory conditions. Mice lacking AHR in eosinophils expanded innate lymphoid cells of type 2 and cleared Nippostrongylus brasiliensis infection more effectively than did wild-type mice. These results highlight the heterogeneity of eosinophils in response to tissue cues and identify a unique AHR-dependent subset of eosinophils in the small intestine with an immunomodulatory profile.

Structural Elucidation and Prognostic Relevance of 297-11A-Sulfated Glycans in Ovarian Carcinoma.

Ovarian carcinoma is usually diagnosed at an advanced stage with peritoneal dissemination and/or lymph node metastasis, and the prognosis for such advanced carcinoma is very poor. Therefore, new biomarkers to predict patient prognosis are needed. Miyamoto et al. previously showed that keratan sulfate (KS) detected by the 5D4 monoclonal antibody was expressed in ovarian carcinoma. However, the detailed structure of such KS was not determined, and the biological significance of this finding remained to be clarified. We previously generated the 297-11A monoclonal antibody, which recognizes galactose (Gal)-6-O-sulfated N-acetyllactosamine (LacNAc) located at the nonreducing terminus. Because the 297-11A epitope overlaps with that of 5D4, here we chose to use the 297-11A antibody as a tool to analyze KS and related structures. We conducted immunohistochemical analysis of 98 ovarian carcinoma cases with 297-11A antibody combined with a series of glycosidases and performed mass spectrometry analysis of the human serous ovarian carcinoma cell line OVCAR-3 to deduce the glycan structure of 297-11A-sulfated glycans. We also performed western blot analysis to assess a potential association of 297-11A-sulfated glycans with the mucin core protein mucin 16 (MUC16; also known as cancer antigen 125 (CA125)). Finally, we examined the relationship between 297-11A expression and patient prognosis. Consequently, 297-11A-sulfated glycans were primarily expressed in serous and endometrioid carcinomas and poorly expressed in mucinous and clear cell carcinomas. We reveal that structurally, 297-11A-sulfated glycans expressed in ovarian carcinoma are O-glycans carrying partially sialylated, Gal-6-O-sulfated LacNAc and that these glycans are likely displayed on MUC16 mucin core proteins. Of clinical importance is that expression of 297-11A-sulfated glycans correlated with shorter progression-free survival in patients. Thus, 297-11A-sulfated glycans may serve as a predictor of ovarian carcinoma recurrence.

Interobserver agreement of pathologic classification and grading of tumoral intraductal pre-invasive neoplasms of the bile duct.

Current WHO terminology and recent publications have classified tumoral (grossly visible) intraductal pre-invasive neoplasms of bile duct (TIDN) into three categories: intraductal papillary neoplasm of bile duct (IPNB), intraductal papillary oncocytic neoplasm (IOPN), and intraductal tubulopapillary neoplasm (ITPN). A total of 227 cases of TIDN and related lesions ≥3 mm in height were examined by 10 biliary pathologists referring to these 3 categories and two pathologic gradings: two-tiered system (low- and high-grade dysplasia) and modified types 1 and 2 subclassification. Among them, IPNB was the most frequent (183 cases), followed by IOPN (28 cases), while ITPN was rare (2 cases), and interobserver agreement in this classification was "substantial" (κ-value, 0.657). The interobserver agreement of two-tiered grading system of TIDN was "slight" (κ-value, 0.201), while that of modified types 1 and 2 subclassification was "moderate" (κ-value, 0.515), and 42 % were of type 1, and 58 % were of type 2. Type 1 TIDN showed occasional stromal invasion (6.7 %), whereas type 2 TIDN was frequently associated with stromal invasion (49.6 %) (p < 0.01). In conclusion, the classification of TIDN into three categories and modified types 1 and 2 subclassification are a practically applicable classification and grading system for TIDN.

Met-PET uptake index for total tumor resection: identification of 11C-methionine uptake index as a goal for total tumor resection including infiltrating tumor cells in glioblastoma.

Glioblastoma multiforme (GBM) is largely due to glioma stem cells (GSCs) that escape from total resection of gadolinium (Gd)-enhanced tumor on MRI. The aim of this study is to identify the imaging requirements for maximum resection of GBM with infiltrating GSCs. We investigated the relationship of tumor imaging volume between MRI and 11C-methionine (Met)-PET and also the relationship between Met uptake index and tumor activity. In ten patients, tumor-to-contralateral normal brain tissue ratio (TNR) was calculated to evaluate metabolic activity of Met uptake areas which were divided into five subareas by the degrees of TNR. In each GBM, tumor tissue was obtained from subareas showing the positive Met uptake. Immunohistochemistry was performed to examine the tumor proliferative activity and existence of GSCs. In all patients, the volume of Met uptake area at TNR ≦ 1.4 was larger than that of the Gd-enhanced area. The Met uptake area at TNR 1.4 beyond the Gd-enhanced tumor was much wider in high invasiveness-type GBMs than in those of low invasiveness type, and survival was much shorter in the former than the latter types. Immunohistochemistry revealed the existence of GSCs in the area showing Met uptake at TNR 1.4 and no Gd enhancement. Areas at TNR > 1.4 included active tumor cells with relatively high Ki-67 labeling index. In addition, it was demonstrated that GSCs could exist beyond the border of Gd-enhanced tumor. Therefore, to obtain maximum resection of GBMs, including infiltrating GSCs, aggressive surgical excision that includes the Met-positive area at TNR 1.4 should be considered.

Pathologic conditions of hard tissue: role of osteoclasts in osteolytic lesion.

Hard tissue homeostasis is regulated by the balance between bone formation by osteoblasts and bone resorption by osteoclasts. This physiologic process allows adaptation to mechanical loading and calcium homeostasis. Under pathologic conditions, however, this process is ill-balanced resulting in either over-resorption or over-formation of hard tissue. Local over-resorption by osteoclasts is typically observed in osteolytic metastases of malignancies, autoimmune arthritis, and giant cell tumor of bone (GCTB). In tumor-related local osteolysis, tumor-derived osteoclast-activating factors induce bone resorption not by directly acting on osteoclasts but by indirectly upregulating receptor activator of NFκB ligand (RANKL) on osteoblastic cells. Similarly, synovial tissue in the autoimmune arthritis model does overexpress RANKL and contains numerous osteoclast precursors, and like a landing craft, when it comes in contact with eroded bone surfaces, osteoclast precursors are immediately polarized to become mature osteoclasts, inducing rapidly progressive bone destruction at a late stage of the disease. GCTB, on the other hand, is a common primary bone tumor, usually arising at the metaphysis of the long bone in young adults. After the discovery of RANKL, the concept of GCTB as a tumor of RANKL-expressing stromal cells was established, and comprehensive exosome studies finally disclosed the causative single-point mutation at histone H3.3 (H3F3A) in stromal cells. Thus, osteolytic lesions under various pathological conditions are ultimately attributable to the overexpression of RANKL, which opens up a common, practical and useful therapeutic target for diverse osteolytic conditions.

Cloning of Helicobacter suis cholesterol α-glucosyltransferase and production of an antibody capable of detecting it in formalin-fixed, paraffin-embedded gastric tissue sections.

Helicobacter suis (H. suis), formerly called Helicobacter heilmannii type 1 (H. heilmannii), is a gram-negative bacterium of the Helicobacter species. This pathogen infects the stomach of humans and animals such as dogs, cats, pigs, and rodents, the latter giving rise to zoonotic infection. Here, we generated a H. suis-specific antibody useful for immunohistochemistry with formalin-fixed, paraffin-embedded tissue sections. To do so, we began by cloning the gene encoding H. suis cholesterol α-glucosyltransferase (αCgT). αCgT is the key enzyme responsible for biosynthesis of cholesteryl α-D-glucopyranoside (CGL), a major cell wall component of Helicobacter species including H. suis. The deduced amino acid sequence of H. suis αCgT had 56% identity with the corresponding Helicobacter pylori (H. pylori). We then developed a polyclonal antibody (anti-Hh-I205R) by immunizing rabbits with a 205 amino acid H. suis αCgT fragment. Immunohistochemistry with the anti-Hh-I205R antibody could differentiate H. suis from H. pylori in gastric mucosa sections derived from mice infected with either pathogen. We then probed formalin-fixed, paraffin-embedded sections of human gastric mucosa positive for H. suis infection with the anti-Hh-I205R antibody and detected positive staining. These results indicate that anti-Hh-I205R antibody is specific for H. suis αCgT and useful to detect H. suis in gastric specimens routinely analyzed in pathological examinations.

Apical membrane expression of distinct sulfated glycans represents a novel marker of cholangiolocellular carcinoma.

Intrahepatic cholangiocarcinoma (ICC) is the second most common primary liver neoplasm, followed by hepatocellular carcinoma. ICC can be further subclassified as (i) perihilar and (ii) peripheral types, the latter histologically resembling small-sized intrahepatic bile ducts, such as interlobular bile ducts, cholangioles/ductules and the canals of Hering. Cholangiolocellular carcinoma (CoCC), now classified by the World Health Organization as a subtype of combined hepatocellular-cholangiocarcinoma, is currently regarded as a subtype of peripheral-type ICC. The present study was undertaken to determine whether sulfated glycans recognized by the MECA-79 monoclonal antibody could serve as a CoCC marker. Using immunohistochemistry, we show that MECA-79 sulfated glycans are preferentially expressed at the apical membrane of cholangiocytes found in small-sized intrahepatic bile ducts in normal liver and in canalicular structures formed in CoCC. We also report that apical membrane MECA-79 sulfated glycan expression colocalizes with that of mucin 1 (MUC1) core proteins. We also present immunoblotting of Chinese hamster ovary cells overexpressing FLAG-tagged MUC1 to show that MUC1 serves as a MECA-79 scaffold. Furthermore, we report that SSP-25 human ICC cells overexpressing N-acetylglucosamine-6-O-sulfotransferase 2 (GlcNAc6ST-2), but not GlcNAc6ST-1, exhibit membrane expression of MECA-79 sulfated glycans, suggesting that GlcNAc6ST-2 catalyzes MECA-79 epitope biosynthesis in cholangiocytes. Moreover, both wild-type and GlcNAc6ST-1 knockout mice exhibit apical membrane MECA-79 expression in small-sized intrahepatic bile ducts, namely interlobular bile ducts, whereas MECA-79 expression was completely absent in comparable tissues from GlcNAc6ST-1 and GlcNAc6ST-2 double knockout mice. These data collectively indicate that apical membrane localization of MUC1 proteins decorated with GlcNAc6ST-2-dependent MECA-79 sulfated glycans may mark cholangiocytes with cholangiolar/ductular differentiation and could serve as a useful CoCC marker.

Inversion of the acetabular labrum triggers rapidly destructive osteoarthritis of the hip: representative case report and proposed etiology.

The pathophysiology of rapidly destructive osteoarthritis (OA) of the hip is unknown. This study documented cases of inversion of the acetabular labrum, which has clinicoradiologic features similar to those of initial-stage rapidly destructive hip OA. Our study was based on a prospective review of data for 9 patients with rapidly destructive hip OA. Intraoperative findings showed that the anterosuperior portion of the acetabular labrum had inverted into the articular space, along with many fragments of articular cartilage, in all patients. Subchondral insufficiency fractures of the femoral heads were seen just under the inverted labra in 8 of the 9 patients. Inversion of the acetabular labrum may be involved in rapid joint-space narrowing and subchondral insufficiency fracture in rapidly destructive hip OA.

Pathologic significance of peribiliary capillary plexus in gallbladder neoplasm.

AIMS: Significance of peribiliary capillary plexus (PCP) in gallbladder neoplasms remains unclear. Aims are to characterize high-grade biliary intraepithelial neoplasm (BilIN), pyloric gland adenoma (PGA), and intracholecystic papillary neoplasm (ICPN), precursors of gallbladder carcinoma, and to differentiate invasive carcinoma from pseudo-invasive lesions in gallbladder walls, referring to PCP. MATERIALS AND METHODS: High-grade BilIN (38 cases), PGA (5 cases), and ICPN (25 cases) were examined using capillary immunostaining. Non-neoplastic gallbladders were used as controls. RESULTS: In non-neoplastic gallbladders, a single layer of regularly dotted capillaries (PCP) was located beneath lining epithelia and around non-neoplastic glands (NNGs), including Rokitansky-Aschoff sinus (RAS), presenting a two-layer of lining epithelia and PCP. Intra-luminal components of all cases of high-grade BilIN and PGA and one-third of ICPNs presented a two-layer pattern. In the remaining ICPNs, capillaries were irregular and sparse in intraluminal neoplastic components presenting irregular and complicated lesions. Neoplastic glands in gallbladder walls of high-grade BilIN and ICPN were classifiable into 2 types: glands that were underlain by densely dotted capillaries and those that were not, with the latter suggestive of invasive carcinoma, while the former suggestive of non-invasive neoplasms involving NNGs intraepithelially and/or showing an expanding growth into gallbladder wall (pseudo-invasion). CONCLUSION: A two-layer pattern of lining epithelia and underlining capillaries were preserved in all cases of high-grade BilIN and PGA and one-third of ICPN cases. Presence or absence of dotted capillaries around neoplastic glands may be able to be added as a new pathologic feature to differentiate invasive carcinomas from pseudo-invasion in gallbladder wall.

Ewing sarcoma of the thoracic epidural space in a young child.

PURPOSE: To report on the clinical course and treatment of Ewing sarcoma of the thoracic epidural space in a 5-year-old girl. METHODS: We present the case of a 5-year-old girl who experienced back pain (day 1); on day 10, the pain had exacerbated and involuntary movements in the lower limbs occurred, and an MRI performed in her local hospital revealed a tumor lesion at the upper thoracic level. RESULTS: On day 13, emergency surgery was performed for partial resection of the tumor. Pathological examination of the resected tumor by immunostaining and gene testing revealed that it was MIC2 positive and an EWS-FLI 1 chimera, respectively, and Ewing sarcoma was diagnosed. The involuntary movements resolved immediately after the surgery. Three weeks after the operation, chemotherapy and radiation therapy were commenced. After 5 months, deep tendon reflexes recovered to normal. MRI showed that the tumor has not recurred at 29 months after surgery. CONCLUSIONS: The majority of epidural patients undergo emergency surgery only after symptom exacerbation, which includes the development of neurological deficits. Thus, preoperative diagnosis of Ewing sarcoma of the epidural space is difficult and diagnosis is frequently made by a post-operative gene test. The resection area is limited to the intralesional margin area because a larger resection is difficult due to the characteristics of the affected region; thus, there is a higher possibility of recurrence and careful follow-up of the case is necessary.

[Specimen misidentification in pathology laboratory: trends and measures].

Specimen misidentification in pathology laboratories may have serious consequences. Reports on the frequency of errors in pathology laboratories in Japan are rare. We reviewed near-miss and incident reports over 7 years in our laboratory, extracted those associated with misidentification, analyzed annual changes in numbers and content, and discussed the problems faced and measures taken to prevent misidentification. Of 113,447 pathological cases, 88 (0.078%) reports were associated with misidentification. Of these 88 misidentification cases, 19% occurred before and during accessioning, 16% during dissecting and sectioning, 30% during embedding, 13% during tissue cutting and slide mounting, 19% during slide submitting, and 3% during diagnosis. Two cases (2.3%) of misidentification were detected after diagnosis; however, misidentification did not appear to cause adverse effects in any patient. The frequency of events is similar to that reported in the literature; specimen misidentification was noted in 0.1-0.2% of cases in a modern pathology laboratory. Two-thirds of misidentification events occurred associated with gross specimens, similar to findings in other studies. With the introduction of new technologies that minimize the possibility of human errors (e.g., barcode reading, digital imaging of every specimen, and installation of a glass slide printer), education on medical safety, and the use of multiple safety nets (e.g., diagnosis cancelling and slide checking), errors have decreased, but have not been eliminated completely. Recording errors and reporting them to the hospital and social community, and maintaining a sustainable quality improvement system is very important to reduce errors in pathology.

Perivascular epithelioid cell tumors (PEComas) of the bone and soft tissue: a Japanese Musculoskeletal Oncology Group (JMOG) multi-institutional study.

PURPOSE: Perivascular epithelioid cell tumors (PEComas) of the bone and soft tissues are rare mesenchymal neoplasms, some of which are malignant. However, their clinical and pathological characteristics remain unclear. This study was performed to investigate the clinical and pathological characteristics of PEComas in bone and soft tissues by leveraging information from the Japanese Musculoskeletal Oncology Group. METHODS: Nine patients, including four male and five female patients with a median age of 50 years, were retrospectively reviewed. PEComas of the visceral organs, including the uterus and retroperitoneum, were excluded. RESULTS: Eight tumors arose in the soft tissue and one in the bone, with a mean size of 8.8 cm. Four patients showed local recurrence or distant metastasis. The 1-year survival rate was 78%. Pathologically, eight tumors were classified as malignant and one as having uncertain malignancy potential. Half of the tumors showed high MIB-1 index values of > 30%. Immunohistochemically, the melanocyte marker HMB45 was expressed in 89% of the cases, and muscle-specific markers were expressed only in 30-50% of the cases. Transcription factor binding to IGHM enhancer 3 (TFE3) expression was positive in 100% of the patients. Tumors with high expression of TFE3 were classified as PEComas with malignant potential according to Folpe's classification. CONCLUSIONS: Bone and soft tissue PEComas may have a higher malignancy potential than other visceral PEComas and are more likely to develop as TFE3-rearranged PEComas.

Ewing sarcoma with very late metastasis in the skull: a case report.

BACKGROUND: Ewing sarcoma is a malignant bone tumor; however, its prognosis has improved since the development of modern chemotherapy. Although Ewing sarcoma outcomes have improved, issues related to late complications, secondary malignant neoplasms, and late recurrence or metastasis have emerged. CASE PRESENTATION: We report a case of Ewing sarcoma that recurred in the occipital bone 21 years after primary tumor treatment. A 45-year-old Japanese woman with a history of Ewing sarcoma 21 years prior, was referred to our hospital due to a severe headache. A tumor was detected in the left occipital bone, and the biopsy revealed Ewing sarcoma. Metastasis was suspected because the patient had been treated for Ewing sarcoma of the left clavicle 21 years prior. There have been several cases of local recurrence or metastasis, occurring 15-20 years after the onset of the initial disease. To our knowledge, very late metastasis of Ewing sarcoma in the skull has not been reported. CONCLUSION: We report a rare case of very late metastasis of Ewing sarcoma in the skull with a review of the literature. Delayed metastasis secondary to Ewing sarcoma can occur in the lung, which is the most common site for metastasis, as well as other regions of the body, such as the cranium.

Expression and Clinical Significance of Spi-B in B-cell Acute Lymphoblastic Leukemia.

Spi-B, a member of the E26 transformation-specific (ETS) family of transcription factors, plays an important role in B cell differentiation. Spi-B also functions in development of diffuse large B-cell lymphoma; thus, we hypothesized that it may participate in leukemogenesis of B-cell acute lymphoblastic leukemia (B-ALL). To test this hypothesis, we first generated an anti-Spi-B monoclonal antibody that recognized Spi-B on formalin-fixed, paraffin-embedded tissue sections. This antibody, designated S28-5, selectively stained B cell nuclei at the pre-plasma cell stage (including centrocytes and centroblasts in germinal centers) and nuclei of plasmacytoid dendritic cells, but not fully differentiated plasma cells, T cells, macrophages, or follicular dendritic cells. Employing S28-5, we then performed immunohistochemical staining of bone marrow aspiration biopsy specimens obtained from B-ALL patients (n=62). Cases that showed stronger nuclear S28-5 signals than T-cell ALL were scored positive. In 26 (42%) of 62 specimens, leukemic cells showed nuclear Spi-B expression, and positivity was associated with patient age at diagnosis, and serum uric acid and creatinine levels. Moreover, Spi-B-positive patients demonstrated significantly shorter overall survival than did Spi-B-negative patients. These results suggest that Spi-B expression may serve as a prognostic indicator of B-ALL.

Primary Ewing's sarcoma/primitive neuroectodermal tumor of the kidney and its clinical features.

Introduction: Ewing sarcoma family tumor is a malignant tumor that is primarily of bone origin; it rarely occurs in the kidney. Case presentation: A 22-year-old woman presented with hematuria. Computed tomography revealed a 6 × 6-cm mass in the lower pole of the right kidney with invasion into the right renal vein. A right laparoscopic radical nephrectomy was performed. The tumor was completely encapsulated. Based on the small-round-cell histology, diffusely CD99-positive tumor cells, and EWS (ex7)-FLi1 (ex6) fusion gene break point transcript, we diagnosed Ewing sarcoma/primitive neuroectodermal tumor of the kidney. After surgery, eight cycles of adjuvant chemotherapy including vincristine, doxorubicin (Adriamycin®), cyclophosphamide, ifosfamide, and etoposide were given. No evidence of recurrence has been observed 13 months from diagnosis. Conclusion: This was a rare Ewing sarcoma family tumor in the kidney of a young female with no remarkable family medical history.

A multi-institutional study of salivary gland cytopathology: Application of the Milan System for Reporting Salivary Gland Cytopathology in Japan.

BACKGROUND: The Milan System for Reporting Salivary Gland Cytopathology (MSRSGC) is a risk-stratification reporting system that was introduced in 2018. The objective of this multi-institutional study was to evaluate the utility of the MSRSGC in Japan. METHODS: In total, 1608 fine-needle aspiration samples with matching histologic diagnoses were retrieved from 12 large institutions in Japan. The diagnostic categories of the MSRSGC were assigned prospectively or retrospectively, and the results were compared with the histologic diagnoses. RESULTS: The cases were classified as follows: nondiagnostic, 18.1%; non-neoplastic, 4.1%; atypia of undetermined significance, 11.5%; neoplasm-benign, 43.7%; salivary gland neoplasm of uncertain malignant potential, 9.6%; suspicious for malignancy, 3.6%; and malignant, 9.4%. The risk of neoplasm and the risk of malignancy in each MSRSGC category were as follows: nondiagnostic, 72.9% and 13.4%, respectively; non-neoplastic, 15.2% and 9.1%, respectively; atypia of undetermined significance, 77.9% and 24.9%, respectively; neoplasm-benign, 99% and 1.8%, respectively; salivary gland neoplasm of uncertain malignant potential, 94.8% and 37%, respectively; suspicious for malignancy, 100% and 89.7%, respectively; and malignant, 100% and 99.3%, respectively. The accuracy of the MSRSGC for diagnosing neoplasms was 97.8%, and its accuracy for diagnosing malignancy was 97.3%. Institutions that used Romanowsky-stained preparations had lower nondiagnostic rates and lower risks of neoplasm and malignancy in the non-neoplastic category. CONCLUSIONS: The MSRSGC is useful for risk stratification and quality control. Widespread use of the MSRSGC would improve the accuracy of salivary gland cytology and lead to better patient care in Japan.

Myxoid type and non-myxoid type of intimal sarcoma in large vessels and heart: review of histological and genetic profiles of 20 cases.

Intimal sarcoma is one of the most common and well-known primary malignant neoplasms of the aorta and heart. The authors reviewed cases of intimal sarcoma from histological, immunohistochemical and genetic perspectives. Twenty cases of intimal sarcoma were retrieved. Immunohistochemistry and FISH of MDM2 and PDGFRA genes were performed. All 20 tumours were composed of spindle-shaped, stellate, oval or polygonal tumour cells with irregular hyperchromatic nuclei arranged in a haphazard pattern, accompanied by nuclear pleomorphism and frequent mitotic figures. Other histological findings were as follows: abnormal mitosis in 10 cases (50%), necrosis in 15 cases (75%), myxoid stroma in 12 cases (60%), cartilaginous formation in 1 case (5%), haemorrhage in 12 cases (60%) and fibrinous deposition in 14 cases (70%). The tumours were positive for MDM2 in 16 cases (80%), ERG in 4 cases (20%), alpha-smooth muscle actin in 6 cases (30%), desmin in 5 cases (25%) and AE1/AE3 in 4 cases (20%). Immunohistochemical positivity was focal in each case. Loss of H3K27me3 expression was noted in 2 cases (10%). MDM2 and PDGFRA gene amplifications were detected in 11 cases (55%) and 1 case (5%), respectively. Fisher's exact test revealed a significant correlation between MDM2 gene amplification and myxoid stroma (p = 0.0194). No parameters showed any association with the anatomical location of the tumours. It was suggested that myxoid histology of intimal sarcoma may be associated with MDM2 gene amplification and that intimal sarcoma may be divided into myxoid and non-myxoid types.

A case of systemic anaplastic large cell lymphoma with 'Hodgkin-like' appearance and skin involvement mimicking lymphomatoid papulosis.

We report a unique case of the CD30+ anaplastic large cell lymphoma (ALCL). A 44-year-old Japanese male presented with lymphadenopathy followed by skin involvement. Initially, a swollen cervical lymph node was recognized in 1989 and relapsed in 1991, which was histologically diagnosed as Hodgkin disease of nodular sclerotic type. In 1996, he presented ulcerative cutaneous nodules and swollen lymph nodes in his left inguinal region, which was then diagnosed with CD30+ ALCL. Both the lymphadenopathy and the skin lesion had been completely remitted by combining chemotherapy followed by radiotherapy. Thereafter, he had relapsing and remitting episodes of multiple papules and nodules on his face, trunk and extremities for 10 years. Repeated histopathological examination revealed similar tumor cell proliferation in the papules/nodules of the skin. Essentially similar immunohistochemical features, including CD30 and granzyme B expression, but not anaplastic lymphoma kinase (ALK), strongly suggested that all these tumors were sequential expression of one disease continued for 19 years. This case was finally diagnosed as CD30+ ALCL with unique skin involvement mimicking lymphomatoid papulosis (LyP).

The Conspicuousness of High Endothelial Venules in Angioimmunoblastic T-cell Lymphoma Is Due to Increased Cross-sectional Area, Not Increased Distribution Density.

Angioimmunoblastic T-cell lymphoma (AITL) is a T-cell lymphoma of follicular helper T-cell origin. Histologically, neoplastic T-cells proliferate to form clusters adjacent to or between arborizing high endothelial venules (HEVs). HEVs in normal lymph nodes express sulfated glycans called peripheral lymph node addressin (PNAd); however, it remains unclear whether PNAd is also expressed on HEVs in AITL. Furthermore, although it is widely accepted that HEVs are conspicuous in AITL due to their proliferation, quantitative histological support for this concept is lacking. To investigate these issues, we employed monoclonal antibodies recognizing PNAd, namely, MECA-79, HECA-452, and 297-11A, and performed quantitative immunohistochemical analysis of HEVs in 36 AITL-affected and 67 normal lymph nodes. Staining with all three antibodies confirmed that AITL HEVs express PNAd. Moreover, AITL HEVs were bound calcium-dependently by L-selectin-IgM fusion proteins, indicating that they function in the recruitment of L-selectin-expressing lymphocytes. Unexpectedly, HEV distribution density was not increased but rather decreased in AITL compared with normal lymph nodes, but HEV cross-sectional area in AITL was significantly greater than that seen in normal lymph nodes. Overall, these results indicate that the prominence of AITL HEVs is likely due to increased cross-sectional area rather than increased distribution density.

Apical Membrane Expression of Distinct Sulfated Glycans Is a Characteristic Feature of Ductules and Their Reactive and Neoplastic Counterparts.

Intrahepatic bile ducts transport bile between bile canaliculi and the extrahepatic bile duct. The luminal surface of this tract is lined by a layer of biliary epithelial cells, or cholangiocytes, which secrete mucins consisting of scaffold proteins and O-glycosidically linked carbohydrate side chains. Although mucin core proteins have been extensively investigated, the structure and function of carbohydrate side chains have not. Here, we demonstrate that distinct sulfated glycans positive for MECA-79, R-10G, and 297-11A, but not 5D4, monoclonal antibodies are expressed in the cytoplasm of cells of large-sized ducts and in the apical membrane of cells in ductules, and that R-10G immunolabeling is partially eliminated by endo-ß-galactosidase digestion, supporting the presence of N-acetylglucosamine-6-O-sulfated N-acetyllactosamine structures. We observed comparable apical membrane-predominant staining in ductular reactions seen during regeneration that occurs in various liver diseases and in cholangiolocarcinoma, a subtype of small duct-type intrahepatic cholangiocarcinoma (iCCA). Apical membrane expression of distinct sulfated glycans in large duct-type iCCA was negligible. Intriguingly, under pathological conditions, endo-ß-galactosidase digestion almost completely eliminated R-10G immunoreactivity. These findings suggest that apical membrane expression of distinct sulfated glycans is a characteristic feature of ductules and their reactive and neoplastic counterparts.