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.

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.

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.

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.

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.

The nature of the white opaque substance within colorectal neoplastic epithelium as visualized by magnifying endoscopy with narrow-band imaging.

Background and study aims: We previously reported our discovery of a white opaque substance (WOS) that is opaque to endoscopic light inside the epithelium while using magnifying endoscopy (ME) to examine gastric epithelial neoplasia. Histopathologic analysis revealed that the WOS comprises minute lipid droplets (LDs) accumulated within the neoplastic epithelium. In addition, the WOS was found in colorectal epithelial neoplasia, although it was unclear whether this WOS corresponded to an accumulation of LDs, as in the stomach. Therefore, the aim of the current study was to elucidate whether the WOS observed in colorectal epithelial tumors comprises LDs. Patients and methods: A consecutive series of 40 WOS-positive and 40 WOS-negative colorectal epithelial tumors was analyzed. One biopsy specimen was taken from each neoplasm. Cryostat sections were stained with oil red O for LD, and sections after formalin-fixation for LD were immunostained with anti-adipophilin antibody. Results: The prevalence of LDs stained with oil red O in WOS-positive vs. WOS-negative lesions was 47.5 % (19/40) vs. 5 % (2/40), respectively (P < 0.001). Furthermore, the WOS coincided with the expression of adipophilin; the prevalence of LDs stained by anti-adipophilin antibody in WOS-positive vs. WOS-negative lesions was 100 % (40/40) vs. 62.5 % (25/40), respectively (P < 0.001). Conclusions: This study elucidated for the first time that endoscopically visualized WOS in colorectal epithelial neoplasia may be composed of LDs accumulated in the neoplastic epithelium.

Pemetrexed-induced scleroderma-like conditions in the lower legs of a patient with non-small cell lung carcinoma.

Pemetrexed, which is used for the treatment of non-small cell lung carcinoma and malignant mesothelioma, induces cutaneous adverse reactions in approximately 20% of patients. There are also reports of the induction of fibrosing disorders. We describe a case of pemetrexed-induced scleroderma-like conditions in the lower legs of a patient whose pulmonary carcinoma has been relatively well controlled, with prolongation of the dose interval, in spite of the discomfort in both his legs. Skin biopsy revealed dermal fibrosis and dilated lymph vessels in the dermis, but lymphocytic infiltration around the lymph vessels, in contrast to the blood vessels, was minimal. Immunohistochemical staining revealed that the major subsets of T cells that had infiltrated around blood vessels were CD3 and CD45Ro, but no B cells were detected. High serum levels of interleukin (IL)-4 and IL-6 suggested that T cells, which secrete these cytokines, may be involved in the pathogenesis of this condition. Magnetic resonance imaging of the lower extremities revealed muscular and fascial involvement. Several chemotherapeutic agents, such as taxanes, gemcitabine and bleomycin, are known to induce scleroderma-like changes, and we should also keep the side-effects of pemetrexed in mind when we encounter patients with fibrosing conditions.

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.

Significant expression of thyroid transcription factor-1 in pulmonary squamous cell carcinoma detected by SPT24 monoclonal antibody and CSA-II system.

In contrast to the usefulness of thyroid transcription factor-1 (TTF-1) in distinguishing primary adenocarcinoma of the lung from metastatic lesions, TTF-1 expression in pulmonary squamous cell carcinoma is reported to be at low level and not a suitable immunohistochemical marker. We hypothesized that the highly sensitive detection system, CSA-II, can visualize even faint expression of TTF-1 in pulmonary squamous cell carcinoma. In this study, 2 commercially available clones of TTF-1 monoclonal antibody, 8G7G3/1 and SPT24, were used for staining 38 cases of pulmonary squamous cell carcinoma, in combination with the CSA-II and the conventional detection system, EnVision. The combined use of the 8G7G3/1 clone with EnVision and CSA-II showed a positive reaction in only 1 and 4 cases, respectively. The use of SPT24 clone showed positive staining in 5 cases with EnVision and in 20 of 38 cases (52.6%) with the CSA-II. Interestingly, positive staining by the SPT24-CSA-II technique of samples from tissue blocks preserved for <2 years was 73.6% compared with only 31.5% in those preserved for >2 years. In addition, a 6-month preservation of the cut sections resulted in stain fading and decreased positivity (50%), compared with freshly cut sections. We conclude that the use of the SPT24 monoclonal antibody with the CSA-II system can detect even weak expression of TTF-1 in pulmonary squamous cell carcinoma. This staining technique can potentially allow the discrimination of primary squamous cell carcinoma of the lung from metastatic lesions, especially in freshly prepared paraffin sections.

Mammalian target of rapamycin signaling activation patterns in pancreatic neuroendocrine tumors.

BACKGROUND: Phosphatidylinositol 3-kinase/Akt/mammalian target of rapamycin (mTOR) pathway dysregulation has been implicated in the development of various human cancers. However, expression of mTOR cascade components in pancreatic neuroendocrine tumors (PNETs) has not been fully explored. The aim of this study was to assess the expression of mTOR pathway in PNETs using immunohistochemistry. METHODS: From December 1984 to April 2012, we surgically treated 42 patients with PNETs. We used immunohistochemistry to evaluate expression of mTOR, phosphorylated mTOR (p-mTOR), p70S6 kinase (S6K), phosphorylated S6 ribosomal protein (p-S6rp), eukaryotic initiation factor 4E-binding protein 1 (4E-BP1), and phosphorylated 4E-BP1 (p-4E-BP1) in the resected specimens. The relation between the expression of these molecules and clinicopathological characteristics was investigated. RESULTS: We identified the expression of mTOR (28.6%), p-mTOR (52.4%), S6K (52.4%), p-S6rp (40.5%), 4E-BP1 (81.0%), and p-4E-BP1 (26.2%) in PNETs. The expression of mTOR, p-mTOR, S6K, and p-S6rp was significantly associated with tumor invasion, proliferation, and an advanced-stage. Particularly, the expression of p-mTOR was related to clinically relevant factors such as tumor size, vascular invasion, extrapancreatic invasion, lymph node and/or distant metastasis, mitotic count, and European Neuroendocrine Tumor Society TNM staging as well as the 2004 and 2010 World Health Organization (WHO) classification. In addition, p-S6rp expression was related to vascular invasion, extrapancreatic invasion, lymph node and distant metastasis, mitotic count, and the 2010 WHO classification. In contrast, no significant relation between 4E-BP1 activation and clinicopathological factors was observed. The expression of p-mTOR was strongly correlated with that of p-S6rp (r = 0.474, P = 0.002). CONCLUSIONS: Our results suggest that activation of the mTOR/S6K signaling pathway plays a significant role in tumorigenesis and progression of PNET.