A Case of Methotrexate-Associated Lymphoproliferative Disorder (Lymphomatoid Granulomatosis) of the Skin.

Iatrogenic lymphoproliferative disorder (LPD) can develop in patients treated with immunosuppressive drugs for autoimmune or other inflammatory diseases. Here, we report a case of lymphomatoid granulomatosis of the skin that occurred as a methotrexate (MTX)-associated LPD. We also review the relevant literature. A 73-year-old woman presented to our department with an approximately 10-year history of MTX therapy for rheumatoid arthritis. Three months earlier, she noticed a small nodule in her right upper arm. It gradually enlarged, and the center began to decay. Grossly, the lesion was 40 × 40 mm in size with ulceration, and the surrounding skin presented dark red erythema. A biopsy specimen was taken for definitive diagnosis. Histologically, infiltrating growth of medium-to-large atypical lymphocytes was observed underneath the ulceration and was accompanied by small reactive lymphocytes. The atypical lymphocytes demonstrated a tendency to infiltrate the vessels, which showed an angiocentric pattern. Immunohistochemistry revealed that the atypical lymphoid cells were positive for CD79a, CD20, and CD30. In addition, in situ hybridization for Epstein-Barr virus (EBV) revealed expression of EBV-encoded small RNAs. The patient was diagnosed with MTX-associated LPD (lymphomatoid granulomatosis), owing to her history of MTX treatment, the expression of the atypical lymphocytes for B-cell markers and EBV-encoded small RNA, and the angiocentric infiltrating pattern. The lesion reportedly disappeared after withdrawal of MTX.

A case of anaplastic lymphoma kinase-positive renal cell carcinoma coincident with Hodgkin lymphoma.

We report a case of ALK-positive renal cell carcinoma coincident with Hodgkin lymphoma. The patient was a 19 year-old-girl without sickle cell trait. The right renal tumor was discovered concomitantly with Hodgkin lymphoma (HL). After chemotherapy for HL, right nephrectomy was performed. Microscopically, the tumor showed a solid and focally pseudo-papillary growth pattern studded with tubular structures. Most tumor cells were small bland eosinophilic cells, but rhabdoid cells, vacuolated cells, pleomorphic multinucleated giant cells were also admixed. The variety of growth patterns and cell features led us to speculate a possibility of ALK-positive renal cell carcinoma (ALK + RCC). ALK was immunohistochemically positive, and fluorescence in situ hybridization analysis detected a split signal of the ALK gene. We examined previously reported partner genes (STRN, TPM3, VCL and EML4) by RT-PCR, but fusion gene was not detected. RCC showing solid or cribriform growth patterns with vacuolated cells with intracytoplamic lumina, rhabdoid cells, and mucus production indicates the possibility of ALK + RCC.

Gastric lanthanosis (lanthanum deposition) in dialysis patients treated with lanthanum carbonate.

Lanthanum carbonate (LaC) is used to prevent hyperphosphatemia in dialysis patients. It is commonly believed that there is little LaC absorption from the intestines. However, La deposition in the gastric mucosa, which we coined "gastric lanthanosis", was recently reported. We describe here the clinicopathological features of and a possible mechanism for gastric lanthanosis. This study included 23 patients with definite gastric lanthanosis. We extracted characteristic clinicopathological features of gastric lanthanosis by computed tomography (CT) imaging and endoscopic, histologic, electron-microscopic, and element analysis examinations. The Helicobacter pylori infection rate in the lanthanosis group was much lower than that among the general population. The clinicopathological features characteristic of gastric lanthanosis were mucosal high-density linear appearance by CT, reflective bright-white spots (BWS) by gastroscopy, eosinophilic histiocytes occasionally phagocytizing foreign materials by histology, and numerous electron-dense particles in the histiocytes. The particles had burr-like skeletons resembling La crystals. Gastric lanthanosis is an under-reported, but not a rare lesion. It is characterized by endoscopic BWS and histologic eosinophilic histiocytes in dialysis patients treated with LaC. The proposed mechanism for gastric lanthanosis is that LaC is dissolved by gastric juice, crystallized within the mucosa and is phagocytized by histiocytes.

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.

White opaque substance represents an intracytoplasmic accumulation of lipid droplets: immunohistochemical and immunoelectron microscopic investigation of 26 cases.

BACKGROUND AND AIM: White opaque substance (WOS) in gastric neoplasias is a unique finding visualized in magnifying endoscopy (ME) with narrow band imaging (NBI) and it represents intramucosal accumulation of lipid droplets using oil red O staining. METHODS: Subjects were 26 WOS-positive (13 adenomas and 13 well-differentiated adenocarcinomas) and 27 WOS-negative gastric epithelial neoplasias. We carried out immunohistochemical staining using a monoclonal antibody specific for adipophilin as a marker of lipids. Immunoelectron microscopy was used to evaluate morphology of the lipid droplets. RESULTS: Adipophilin was detected in 24 of 25 (96.0%) WOS-positive neoplasias, but it was detected in only two of 27 (7.4%) WOS-negative neoplasias. Lipid droplets were only seen in the surface epithelium in 10 of 11 (91.1%) adenomas, whereas the lipid droplets also existed in the cryptal epithelium in seven of 13 (53.8%) adenocarcinomas. Immunoelectron microscopy revealed numerous lipid droplets mainly existing in the subnuclear cytoplasm of the epithelium. The shape of the lipid droplets in adenomas was round and uniform, whereas that in adenocarcinomas was irregular. CONCLUSIONS: The present study confirmed that the presence of WOS in gastric neoplasias was dependent upon intramucosal accumulation of lipid droplets using anti-adipophilin staining. Intraepithelial distribution and morphology of the lipid droplets differed between adenoma and adenocarcinoma.

Induction of GNE in myofibers after muscle injury.

OBJECTIVE: The aim of the present study was to clarify the expression of uridine diphospho-N-acetylglucosamine 2-epimerase/N-acetylmannosamine kinase (GNE) protein and mRNA in damaged or regenerating myofibers. METHODS: We investigated the muscle expression pattern of GNE protein by immunohistochemistry using a murine model involving intramuscular injection of cardiotoxin (CTX), and the expression level of GNE mRNA by quantitative real-time polymerase chain reaction analysis of damaged or regenerating myofibers that had been collected directly from tissue sections using laser-capture microdissection. RESULTS: The expression of GNE protein was increased in severely damaged myofibers as well as in regenerating myofibers with central nuclei, both of which also showed an increase in the expression of GNE mRNA. In regenerating myofibers, immunoreactivity for GNE protein in nuclei relative to that in the cytoplasm was higher at 7 days than at 4 days after CTX injection. CONCLUSION: Our findings suggest that GNE expression is induced when myofibers are damaged or regenerating, and that GNE plays a role in muscle regeneration.

Rescue of mutant alpha-galactosidase A in the endoplasmic reticulum by 1-deoxygalactonojirimycin leads to trafficking to lysosomes.

Active-site-specific chaperone therapy for Fabry disease is a genotype-specific therapy using a competitive inhibitor, 1-deoxygalactonojirimycin (DGJ). To elucidate the mechanism of enhancing alpha-galactosidase A (alpha-Gal A) activity by DGJ-treatment, we studied the degradation of a mutant protein and the effect of DGJ in the endoplasmic reticulum (ER). We first established an in vitro translation and translocation system using rabbit reticulocyte lysates and canine pancreas microsomal vesicles for a study on the stability of mutant alpha-Gal A with an amino acid substitution (R301Q) in the ER. R301Q was rapidly degraded, but no degradation of wild-type alpha-Gal A was observed when microsomal vesicles containing wild-type or R301Q alpha-Gal A were isolated and incubated. A pulse-chase experiment on R301Q-expressing TgM/KO mouse fibroblasts showed rapid degradation of R301Q, and its degradation was blocked by the addition of lactacystin, indicating that R301Q was degraded by ER-associated degradation (ERAD). Rapid degradation of R301Q was also observed in TgM/KO mouse fibroblasts treated with brefeldin A, and the amount of R301Q enzyme markedly increased by pretreatment with DGJ starting 12 h prior to addition of brefeldin A. The enhancement of alpha-Gal A activity and its protein level by DGJ-treatment was selectively observed in brefeldin A-treated COS-7 cells expressing R301Q but not in cells expressing the wild-type alpha-Gal A. Observation by immunoelectron microscopy showed that the localization of R301Q in COS-7 cells was in the lysosomes, not the ER. These data suggest that the rescue of R301Q from ERAD is a key step for normalization of intracellular trafficking of R301Q.

Aberrant expression of BAFF receptor, a member of the tumor necrosis factor receptor family, in malignant cells of nonhematopoietic origins.

The acquired capability of evading apoptosis is one of the prerequisites for cancer development, and NF-kappaB plays a critical role by inducing anti-apoptotic molecules. In this study, we firstly carried out an expression-cloning approach to isolate the responsible molecules in the NF-kappaB activation pathway with the defective mutant cell line, COS-A717. This cell line shows reduced constitutive basal activity of NF-kappaB as compared with the parental COS cells. We successfully isolated genes with compensating activity for the pathway, and one gene encoded B-cell activating factor receptor (BAFF-R). However, a Northern blot analysis revealed that the BAFF-R expression is not only limited to cells of B cell origin, but also is found in those with nonhematopoietic origins. In the human fibrosarcoma cell line HT1080, an immunohistochemical analysis revealed that the expression of BAFF-R is not on the cell surface, but in the cytoplasm. The expression of BAFF was also detected, and the reduction of endogenous BAFF or BAFF-R by siRNA decreased the basal NF-kappaB activity. Lastly, from clinicopathological specimens, the associated expression of BAFF-R and BAFF was demonstrated in osteosarcoma. We propose that an aberrant BAFF/BAFF-R-dependent autocrine mechanism may play a role in the development of certain types of cancer cells.

Merkel cell carcinoma co-existent with sebaceous carcinoma of the eyelid.

Merkel cell carcinoma is occasionally associated with other types of cutaneous malignancies including squamous cell carcinoma, basal cell carcinoma and lentigo maligna. We report a case of Merkel cell carcinoma co-existent with sebaceous carcinoma in the right upper eyelid of a 61-year-old Japanese man. Histopathologically, the resected tumor consisted of three nodules located in the tarsal plate, showing two distinct histopathological types. Two nodules were Merkel cell carcinoma and located in the proximal part of the palpebral conjunctiva. The third was sebaceous carcinoma located in the distal transitional zone between the epidermis and the conjunctiva. No features of transition between these two components were noted. Metastatic deposits were identified in the regional lymph nodes, which solely consisted of Merkel cell carcinoma without sebaceous carcinoma. This is the first report of such co-existent lesions.

A Biotin Tagging Immunoelectron Microscopy for Paraffin-embedded Sections.

We herein introduce a novel method of biotin tagging immunoelectron microscopy for formalin-fixed, paraffin-embedded sections. This method was developed to utilize the antigenicity of biotin on epoxy-embedded ultrathin sections that could readily be recovered by a previously established antigen retrieval method as most monoclonal antibodies failed to recognize their targets by immunoelectron microscopy following antigen retrieval. The biotin tagging method was composed of preembedding immunostaining, epoxy-embedding and sectioning, and postembedding immunostaining steps. The preembedding step utilized the streptavidin-biotin-peroxidase complex method for immunohistochemistry to tag every antigen with a biotin in 3-µm thick paraffin-embedded sections. Next, fixation and processing for transmission electron microscopy (TEM) were performed on sections on glass slides, and ultrathin sections were prepared in epoxy-embedded blocks. In the postembedding step, antigen retrieval was followed by serial incubations with an antibiotin monoclonal antibody and anti-mouse IgG-labeled gold particles. The results obtained using antibodies against a variety of intracellular targets were satisfactory; positive gold particles were observed corresponding to targeted intracellular structures. This study demonstrated that the biotin tagging method was a convenient approach for successful labeling of paraffin-embedded sections for TEM using monoclonal antibodies, although it has relatively poor subcellular labeling quality.

Cutaneous histopathology of the tick-bite region in severe fever with thrombocytopenia syndrome.

A case of severe fever with thrombocytopenia syndrome (SFTS) in which a skin biopsy from the tick-bite region was analyzed is reported. The patient was a 72-year-old woman who developed fever and thrombocytopenia after a tick bite. SFTS was diagnosed from polymerase chain reaction (PCR) analysis of a blood sample. Histopathological analysis of a skin biopsy specimen from the tick-bite region showed CD20-positive perivascular and interstitial immunoblastic cells, which were positive to anti-SFTS virus (SFTSV) nucleoprotein antibody. In addition, SFTSV RNA was detected by real-time PCR from this biopsy specimen. Moreover, hemophagocytosis was also found in the tick-bite region. To the best of our knowledge, this is the first report to analyze the details of the tick-bite region of skin in SFTS, and the first to detect virus-infected cells in the skin. The present findings may help elucidate the mechanisms of entry of SFTSV.

Aberrant methylation in promoter regions of cyclin-dependent kinase inhibitor genes in adenoid cystic carcinoma of the salivary gland.

Adenoid cystic carcinoma (ACC) is a common malignant neoplasm of the salivary gland. The mechanism underlying ACC carcinogenesis is not fully elucidated, although data on associated genetic alterations are accumulating. Cyclin-dependent kinase inhibitors (CKIs) act as tumor suppressors in various cancers, and aberrant methylation in the CKI gene promoter region has been linked to gene silencing and downregulation of expression. The present study investigated methylation of CKI genes, p15, p18, p19, p21, and p27, in 34 cases of ACC. We found frequent and plural methylations of these genes in most cases (68.8% in p15, 90.3% in p18, 78.8% in p19, 92.3% in p21, and 26.5% in p27). Cell cycle disruption induced by these epigenetic aberrations might be important in the tumorigenesis of ACC.

Mutational analysis of Wnt signaling molecules in ameloblastoma with aberrant nuclear expression of beta-catenin.

BACKGROUND: To clarify the genetic background of ameloblastoma, expression of beta-catenin, and mutational status of genes involved in Wnt signaling pathway were investigated. METHODS: We analyzed beta-catenin and cyclin D1 in 18 cases of ameloblastoma by immunohistochemical staining, and searched for mutations in CTNNB1 (gene for beta-catenin), APC, AXIN1, and AXIN2 by polymerase chain reaction (PCR) and direct sequencing method. RESULT: We detected membranous and occasionally cytoplasmic expression of beta-catenin in 16 of 18 cases (89%), and nuclear expression of beta-catenin principally in the peripheral columnar cells in 11 of 18 cases (61%). In nine of the 18 cases (50%), we detected the expression of cyclin D1 principally in the peripheral columnar cells. However, there was no correlation between nuclear expressions of beta-catenin and cyclin D1. No missense mutations were found in CTNNB1, APC, AXIN1, and AXIN2 in all cases except for silent mutation and already-known single nucleotide polymorphism. CONCLUSION: Mutations in CTNNB1, APC, AXIN1, and AXIN2 are not implicated in nuclear accumulation of beta-catenin, and that the expression of cyclin D1 is accelerated independently of beta-catenin in ameloblastomas. Other Wnt signaling members or alternative pathways involved in the degradation of beta-catenin should be subject of further investigation.

A case of sebaceoma with extensive apocrine differentiation.

Apocrine differentiation is a rare event in sebaceoma, and only 3 cases have been reported. We report a case of sebaceoma with extensive apocrine differentiation on the scalp in a 73-year-old Japanese woman. The resected tumor was located entirely within the dermis and subcutis as a well-circumscribed, lobulated, solid, and partially cystic mass, measuring 35 mm at the largest diameter. Histopathologically, it was composed of uniform basaloid cells with clusters of sebocytes, squamous islands of ductal structures, and apocrine cells with apparent decapitation secretion. Nuclear atypia of all types of cells was inconspicuous, and mitotic figures were infrequent. We considered the lesion to be a sebaceoma with apocrine differentiation.

Difference in transducin-like enhancer of split 1 protein expression between basal cell adenomas and basal cell adenocarcinomas - an immunohistochemical study.

BACKGROUND: Basal cell adenoma (BCA) and basal cell adenocarcinoma (BCAC) are benign and malignant, basaloid salivary gland neoplasms, respectively. These tumors show a dual-cell proliferation of inner luminal/ductal cells and outer abluminal/myoepithelial or basal cells. The only difference between them is defined as a malignant morphology such as invasion. Recently, the nuclear expression of ß-catenin and a catenin beta-1 (CTNNB1) mutation were found in BCA. Transducin-like enhancer of split 1 (TLE1) belongs to the Groucho/TLE family, and it functions in the "off" state in the Wnt/ß-catenin signaling pathway. We hypothesized that if the dysregulation of the Wnt/ß-catenin signaling pathway could be attributed to the tumorigenesis of BCA/BCAC, there might be differences in TLE1 expression between BCA and BCAC. METHOD: The study included 35 BCA and 4 BCAC cases. We performed immunohistochemistry to detect TLE1 and ß-catenin and investigated the catenin beta-1 (CTNNB1) mutational profile among BCA and BCAC cases. RESULTS: In BCA, the expression of TLE1 was confined to luminal cells of glandular structures, in contrast to the expression of ß-catenin in abluminal cells. The BCA cases harbored CTNNB1 gene mutations (12/35). In BCAC, luminal cell staining of TLE1 was identical to BCA in non-invasive areas (4/4) but indistinct in invasive areas (3/4). The BCAC cases were ß-catenin positive for abluminal cells in both areas. The BCAC cases had CTNNB1 mutation (2/4) and the laser-captured microdissection allowed the separate collection of infiltrative and non-infiltrative areas to detect the same mutation. CONCLUSIONS: Immunohistochemical analysis for TLE1 can identify BCA and BCAC by luminal cell staining difference, especially indistinct luminal cell expression for TLE1 in invasive areas of BCAC. Moreover, TLE1 can be luminal/ductal cell markers.

Carcinosarcoma ex recurrent pleomorphic adenoma of the submandibular gland.

We report a case of carcinosarcoma ex recurrent pleomorphic adenoma in the submandibular region of a 56-year-old Japanese man. He presented with a 2-year history of a rapidly growing mass in the submandibular region. He reported undergoing excision of a nodule in the same region 10 years earlier. Incisional biopsy confirmed the diagnosis of pleomorphic adenoma. The lesion was excised surgically. The resected tumor measured 40 x 20 mm and was composed of two large nodules and multiple small satellite nodules in the subcutaneous tissue. Histopathologically, one large nodule was carcinosarcoma while the other large nodules and small satellite nodules were pleomorphic adenoma. The former large nodule showed a variegated pattern with carcinomatous components (poorly differentiated adenocarcinoma, salivary duct carcinoma, squamous cell carcinoma and undifferentiated carcinoma) and sarcomatous components (spindle cell sarcoma, chondrosarcoma, liposarcoma and rhabdomyosarcoma). Based on the clinical history and histopathology, we consider the lesion to have originated from recurrent pleomorphic adenoma.

Florid cystic endosalpingiosis of the spleen.

A case of endosalpingiosis appearing as a huge multilocular cyst in the spleen of a 31-year-old woman is reported. The cystic lumens were smooth, and lined by fallopian tubal epithelium containing ciliated and secretory cells. The epithelial lining showed neither atypia nor foci of papillary proliferation, with only 3-5% MIB-1 labeling index. The epithelial lining was histochemically negative for mucin, but positive for MUC1 and progesterone receptor. Despite the appearance of a tumor-like mass, it was diagnosed as florid cystic endosalpingiosis as there was a normal tube-like epithelium. Regarding etiology, it was considered to derive from the secondary müllerian system of the splenic capsule.