Ippei Tahara

Spindle cell oncocytoma of adenohypophysis: Report of a case and immunohistochemical review of literature

We present a case of spindle cell oncocytoma (SCO) of the adenohypophysis in a 70-year-old Vietnamese male. The patient was admitted to Cho Ray Hospital after suffering from headache and visual disturbance for 6 months. Clinicians detected a 60×55×45 mm(3) mass located in the suprasellar-sellar region. Histopathologically, the resected tumor was composed of spindle cells with oncocytic appearance. Immunohistochemical examination revealed expression of anti-mitochondria antibody (AMA), vimentin, thyroid transcription factor 1 (TTF-1), epithelial membrane antigen (EMA) and galectin-3. These histologic and immunohistochemical findings are suggestive of SCO.

Genetic alterations of differentiated thyroid carcinoma in iodine‐rich and iodine‐deficient countries

BRAF V600E mutation, RET rearrangements, and RAS mutations are the common genetic alterations in differentiated thyroid carcinomas derived from follicular thyroid cells. However, the relationship between these alterations and iodine intake is still controversial. To clarify the influence of iodine intake on the occurrence of differentiated thyroid carcinomas, we performed molecular analyses for two differentiated carcinomas, papillary thyroid carcinomas (PTCs) and follicular thyroid carcinomas (FTCs), from an iodine‐rich country (Japan) and an iodine‐deficient country (Vietnam). We examined 120 PTCs (67 Japanese and 53 Vietnamese) and 74 FTCs (51 Japanese and 23 Vietnamese). We carried out allele‐specific polymerase chain reaction (AS‐PCR) for BRAF V600E, PCR and direct sequencing for RAS mutations (codon 12, 13, and 61 in NRAS, HRAS, and KRAS), and RT‐PCR for RET/PTC1 and RET/PTC3. BRAF V600E was present in 55/67 (82.1%) Japanese PTCs and 44/53 (83%) Vietnamese PTCs. RET/PTC1 was identified in only one PTC from each country, and no samples had RET/PTC3. NRAS mutation was found in 17/51 (33.3%) Japanese FTCs and 4/23 (17.4%) Vietnamese FTCs. NRAS mutation was cited in codon 61 (20 cases) and codon 12 (one case). None of FTCs had KRAS or HRAS mutations. There were no significant differences in the prevalence of BRAF V600E, RET/PTC, or RAS mutations between the two countries. Our study showed no differences in genetic alterations of thyroid cancers from iodine‐rich and iodine‐deficient countries, possibly suggesting that iodine intake might not affect the genetic alterations of differentiated thyroid cancer.

Immunohistochemical detection of NRASQ61R protein in follicular-patterned thyroid tumors

The NRAS(A182G) mutation, which results in the NRAS(Q61R) protein, is a major driver mutation in follicular-patterned thyroid neoplasms. Although new immunohistochemistry (IHC) for NRAS(Q61R) is now available, its sensitivity, specificity, and diagnostic utility for thyroid tumors are not yet established. We performed IHC for NRAS(Q61R) and direct sequencing for NRAS codon 61 in 4 thyroid cancer-derived cell lines and 98 follicular-patterned thyroid tumors that included 22 follicular thyroid adenomas (FTAs), 35 follicular thyroid carcinomas (FTCs), and 41 cases of nodular hyperplasia (NH). In the tumors with NRAS(Q61R), the expression of BRAF(V600E) was further evaluated immunohistochemically. Two cell lines with NRAS(A182G) showed selective immunoreactivity for NRAS(Q61R). In tumor tissues, NRAS(Q61R) IHC was positive in 18% (4/22), 29% (10/35), and 2% (1/41) of FTAs, FTCs, and NH samples, respectively. The frequencies of the NRAS(Q61R) in FTAs and FTCs were significantly higher than that in NH (P=.046 and P=.001, respectively). All tumors with NRAS(Q61R) expression exhibited uniform cytoplasmic positivity with or without accumulation in their cell membranes. Of the 15 tumors with NRAS(Q61R) expression, 13 cases showed NRAS(A182G) in direct sequencing, whereas all of the tumors without NRAS(Q61R) expression were negative for the mutation. There were no tumors with overlapping expression of NRAS(Q61R) and BRAF(V600E). In reference to the direct sequencing, sensitivity and specificity of the NRAS(Q61R) IHC were 100% and 98%, respectively. In conclusion, NRAS(Q61R) IHC is a highly sensitive and specific tool that is useful for differentiating follicular-patterned thyroid tumors.

Branchial Cleft-Like Cysts Involving 3 Different Organs: Thyroid Gland, Thymus, and Parotid Gland.

Abstract Branchial cleft cysts (BCCs) are also named lateral cervical cysts and widely acknowledged as being derived from embryonic remnants. Lymphoepithelial cysts (LECs) generally show microscopic features that are identical to those of BCCs, and rarely occur at unusual sites or organs. A case of multiple cysts arising in both lobes of the thyroid gland, thymus, and right parotid gland in a 41-year-old man is reported. Clinically, the patient presented with Hashimotos thyroiditis for about 20 years and had past histories of idiopathic thrombocytopenic purpura and severe respiratory infection. This case is unusual in that multiple cysts arose synchronously and/or heterochronously and grew, increasing their sizes in these different organs. Microscopic examinations revealed that all of the cysts were composed of squamous epithelium, dense lymphoid tissue with germinal centers, and a fibrous capsule. These findings corresponded to those of BCCs or LECs. It is notable that the histopathological features were nearly the same in the individual organs. A review of the literature disclosed no previous such reported cases. The etiology is unknown. However, based upon the similar histopathological features of all the excised specimens, common immune and/or hematopoietic disorders may have contributed to their occurrence and development in association with putative genetic abnormalities.

Low frequency of PAX8-PPARγ rearrangement in follicular thyroid carcinomas in Japanese patients

Paired‐box gene 8 (PAX8)‐peroxisome proliferator‐activated receptor‐γ (PPARγ) gene fusion has been identified at significant frequency in follicular thyroid carcinomas (FTCs) with cytogenetically detectable translocation t(2;3)(q13;p25). This represents a possible specific molecular marker for follicular carcinoma. In this study, we examined PAX8‐PPARγ rearrangement in 24 FTC samples from Japanese patients by reverse transcribed‐polymerase chain reaction (RT‐PCR) using two upstream PAX8 primers located in exons 7 and 8 and a downstream primer in exon 1 of PPARγ. The fusion gene was detected in only one of 24 FTCs (4%). The FTC with PAX8‐PPARγ rearrangement from a 56‐year‐old man showed a product consistent with fusion between exon 8 of PAX8 and exon 1 of PPARγ. It was confirmed by direct sequencing. This FTC was histologically encapsulated, composed of trabeculae and small follicles and had complete penetration of the capsule by tumor tissues (minimally invasive type). The frequency of the fusion gene in this study was much lower than the 29–63% noted in reports from other countries suggesting that FTCs in Japanese patients may have a special genetic background, and that the high iodine intake from a typical Japanese diet might influence the frequency of the fusion gene in FTCs.

Multicentric occurrence of multiple papillary thyroid carcinomas –HUMARA and BRAF mutation analysis

Papillary thyroid carcinomas (PTCs) occasionally form multiple tumor foci in different sites of the same thyroid gland. However, it is controversial whether discrete nodules of PTC arise independently (multicentric occurrence) or are seeded from a single tumor via lymphatic channels (intraglandular metastasis). In order to determine the clonal origin of multiple PTCs, we examined X‐chromosome inactivation patterns using a human androgen receptor gene‐based assay (HUMARA) and the BRAF mutation using allele‐specific PCR (AS‐PCR) in 32 microdissected cancerous tissues from 14 Japanese women with multifocal PTC. All tumor foci were greater than 3 mm in size and met the criteria for microscopic classical PTC. Samples from 13 of the 14 patients were informative based on HUMARA. Tumor foci from two cases (15.4%) displayed a discordant X‐chromosome inactivation pattern. Foci from the other 11 cases (84.6%) showed a concordant inactivation pattern of the X‐chromosome. AS‐PCR indicated that BRAF mutational status between the tumor foci was discordant in three (25%) and concordant in nine (75%) of 12 available cases. When the results of these two molecular analyses were combined, 28.6% of the cases were discordant in X‐chromosome inactivation pattern and/or BRAF mutation, suggesting multicentric origin. Some of the remaining concordant cases also may be of multicentric origin. These results support a hypothesis that multicentric occurrence in multiple PTCs may be common, possibly greater than 30%. Although the exact mechanism of multicentric occurrence is still unclear, our findings contribute to the understanding the histogenesis of papillary thyroid carcinoma.

Squamous morula formation in colorectal adenoma: Immunohistochemical and molecular analyses.

Little is known about the squamous morular component (SMC) in colorectal neoplasms because of its rarity. The aim of the present study is to elucidate the morphological, immunohistochemical and genetic characteristics of SMCs in colorectal adenomas. Five colorectal adenomas having SMCs were resected from five patients endoscopically. On immunohistochemical examination (four cases), all SMCs were positive for cytokeratin 5/6 in their cytoplasm and positive for β-catenin in their cytoplasm and nuclei. A nuclear positivity of p63 was detected in one SMC. All SMCs were negative for p53, chromogranin A, synaptophysin and NCAM. There was no Ki-67 expression in any of the SMCs. We detected none of mutations of β-catenin, KRAS and BRAF by microdissection and polymerase chain reaction-direct sequence in any of the four examined SMCs. SMCs are a rare but problematic finding in colorectal adenomas. Using immunohistochemistry for β-catenin, cytokeratin 5/6, Ki-67, p53, chromogranin A, synaptophysin and NCAM can facilitate the diagnosis of these peculiar cell nests.

Gastric adenocarcinoma of pyloric gland type with high-grade malignancy.

To the Editor: Recent advances in mucin histochemistry and immunohistochemistry have clarified the differentiation of gastric adenocarcinoma as gastric type and intestinal type. Gastric type is further divided into foveolar, pyloric gland and fundic gland phenotypes. Here, we report a case of gastric adenocarcinoma with pyloric gland phenotype demonstrated by mucin histochemistry and immunohistochemistry. A 70-year-old Japanese man received distal gastrectomy with lymph node dissection for primary gastric adenocarcinoma. The patient was alive at the time of our review, however, there was local recurrence of the tumor confirmed by endoscopic examination after 5 years from the distal gastrectomy. Gross examination showed a superficial depressed lesion (type 0-IIc), 28 × 15 mm, in the lesser curvature of the middle third of the stomach (Fig. 1a). Histological examination identified proliferation of adenocarcinoma cells which invaded into the subserosal layer. Accurate tumor size was 60 × 40 mm. Microscopic lymph node metastases were detected in 10 of 15 resected lymph nodes. The tumor was composed of acinar, trabecular and insular growth patterns with cuboidal to low columnar cells having mildly basophilic to occasionally coarse granular eosinophilic cytoplasm (Fig. 1b-d). The nuclei were larger than those from normal pyloric gland and were markedly hyperchromatic (Fig. 1b-d). Nuclear inclusions and prominent nucleoli were found intermittently. The mitotic index was high (12 per 10 high power fields). The background mucosa was what would be found in a fundic gland area having incomplete intestinal metaplasia. Samples from the specimen were fixed in 10% buffered formalin, embedded in paraffin, sectioned at 4 μm thick and stained with hematoxylin and eosin. Additionally, histochemical stainings of periodic acid Schiff with diastase (positive for neutral mucin in the gastric foveolar cells, pyloric glands and gastric mucous neck cells) and Alcian blue pH 2.5 (positive for acid mucin in the intestinal goblet cells), and immunohistochemical staining were performed on representative slides. Immunoreactivity was detected using an ENVISION kit protocol (Dako, Glostrup, Denmark) or a Ventana BenchMark GX automated immunostaining system (Tucson, AZ, USA). The neoplastic population was positive for periodic acid Schiff with diastase staining (Fig. 2a) and negative for Alcian blue pH 2.5 staining. Immunohistochemistry demonstrated a strong, diffuse cytoplasmic stain for MUC-6 (Fig. 2b) and a nuclear stain for p53 (Fig. 2c). Over 20% of the neoplastic cells were reactive for Ki-67 (Fig. 2d). There were no immunoreactivities for MUC-2, MUC-5AC, CD10, pepsinogen-I, proton pump/H, K-ATPase α subunit, chromogranin A, α-fetoprotein and trypsin. With reference to a molecular genetic study of pyloric gland adenomas by Matsubara et al., we analyzed the mutation statuses of GNAS and KRAS in the present case. Amplifications of DNAs were performed using HotStarTaq DNA Polymerase (QIAGEN, Tokyo, Japan) by polymerase chain reaction (PCR). Analyses by direct sequencing were performed by BEX Co., Ltd. (Tokyo, Japan). Additional genetic study demonstrated no mutation for GNAS exon 9 or KRAS codons 12/13. Although primary and nested polymerase chain reaction (PCR) reactions were performed, the amplification of GNAS exon 8 was unsuccessful. Based on histology of the current tumor, differential diagnoses includes gastric adenocarcinoma of fundic gland type (chief cell predominant type), neuroendocrine neoplasm, hepatoid adenocarcinoma and pancreatic-type acinar cell carcinoma. However, negative staining for pepsinogen-I (a marker for gastric chief cells and mucous neck cells), proton pump/H, K-ATPase α subunit (for parietal cells), chromogranin A (for neuroendocrine cells), α-fetoprotein (for hepatoid adenocarcinoma cells) and trypsin (for pancreatic acinar cells) excluded these histological subtypes. In addition, neither MUC2 nor CD10 showed intestinal differentiation. The present case was shown to have advanced gastric cancer (pT3 and pN3a), we have demonstrated a gastric adenocarcinoma of pyloric gland type having a high-grade malignancy. The gastric adenocarcinoma of pyloric gland type may appear to be more aggressive than that of fundic gland type, although, further large studies will be required to evaluate the accurate malignant potential of gastric adenocarcinoma of pyloric gland type. Therefore, we must be careful when diagnosing low-grade malignancy with a pathological diagnosis of gastric adenocarcinoma of fundic gland type, especially when biopsy is performed by endoscopy. Gastric type adenocarcinomas occur predominately in old age (69.8 ± 6.4 years); the age of that patient was identical to that of the present case. The lower third of the stomach, which was the most frequent occurred location of gastric type adenocarcinomas, was different from the location in which the present tumor occurred. Furthermore, gastric type adenocarcinomas showed MUC-5AC expression. Accordingly, the present tumor is likely to be different from a gastric type adenocarcinoma. In our speculation, the present case is a malignant counterpart to the pyloric gland adenoma. Pyloric gland adenomas occurred predominately in old age (73 ± 12.8 years) and the gastric corpus, which were identical with the age and the Pathology International 2015; 65: 148–150 doi:10.1111/pin.12241 bs_bs_banner

High expression of CD10 in anaplastic thyroid carcinomas

CD10 is an endopeptidase that degrades various bioactive peptides in the extracellular matrix. In addition to enzymatic degradation, it affects multiple intracellular signal transduction pathways. CD10 expression has been extensively studied in human epithelial cancers of numerous organs and sites. However, its presence in thyroid carcinomas, especially in anaplastic thyroid carcinoma (ATC), has not been fully determined. An actual CD10 expression in thyroid lesions including a large series of ATC was evaluated.

Diagnostic Utility of Prostein, Uroplakin II and SATB2 for Diagnosing Carcinoma of Unknown Primary Origin: A Systematic Immunohistochemical Profiling

Background/Aim: Immunohistochemistry was used to evaluate 600 carcinomas of major histological types from various organs to determine the tissue distributions of the novel markers prostein, uroplakin II and SATB2. Materials and Methods: We retrieved 30 cases from 20 different carcinomas of systemic organs. Results: All prostate adenocarcinomas were immunopositive for prostein, and its reactivity was consistently diffuse. There was faint labeling of prostein in few cases of the 570 non-prostatic carcinomas. Uroplakin II was immunopositive in 53% and 60% of urothelial carcinomas (UC) of the bladder and the ureter, respectively. There was focal and weak positivity of uroplakin II in a few cases of non-urinary tract carcinomas. SATB2 was frequently positive in adenocarcinomas of the digestive organs, and was also expressed in a minority of the non-colorectal adenocarcinomas. Conclusion: Prostein and uroplakin II are immunohistochemical biomarkers of prostate adenocarcinomas and UCs of the urinary tract.