We previously developed γ-glutamyl hydroxymethyl rhodamine green (gGlu-HMRG) as a tool to detect viable cancer cells, based on the fact that the enzyme γ-glutamyltranspeptidase (GGT) is overexpressed on membranes of various cancer cells, but is not expressed in normal tissue. Cleavage of the probe by GGT generates green fluorescence. Here, we examined the feasibility of clinical application of gGlu-HMRG during breast-conserving surgery. We found that fluorescence derived from cleavage of gGlu-HMRG allowed easy discrimination of breast tumors, even those smaller than 1 mm in size, from normal mammary gland tissues, with 92% sensitivity and 94% specificity, within only 5 min after application. We believe this rapid, low-cost method represents a breakthrough in intraoperative margin assessment during breast-conserving surgery.

Human intestinal spirochetosis is a common condition in Western countries, but is not well recognized in Japan. To demonstrate the incidence and clinicopathologic findings of human intestinal spirochetosis in Japan, we retrospectively investigated biopsy, and endoscopically or surgically resected specimens of the large intestine. Among a series of 2556 samples, 11 cases of human intestinal spirochetosis were detected (0.4%). Together with additional nine cases sporadically found, 20 cases of human intestinal spirochetosis were subjected to molecular detection of two strains of spirochetes (Brachyspira aalborgi and Brachyspira pilosicoli) by amplifying species-specific portion of 16S ribosomal RNA and NADH oxydase gene by polymerase chain reaction. B. aalborgi was detected in all cases examined, three of which revealed dual infection of both species. Our results suggest that human intestinal spirochetosis infection is relatively rare, and B. aalborgi is the most prevalent species in Japan. Most of human intestinal spirochetosis were asymptomatic, although symptomatic in exceptional cases. In addition, we emphasize a usefulness of immunostaining with anti-Treponema pallidum and anti-Mycobacterium bovis polyclonal antibodies for detecting the spirochetes.

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.

Biotin-rich intranuclear inclusions, also known as optically clear nuclei, have been observed in various neoplastic and non-neoplastic lesions. They look like nuclei of herpesvirus-infected cells and cause a false-positive immunohistochemical result by avidin-biotin-complex (ABC) method. In the literature, all types of neoplastic lesions with intranuclear inclusions, with one exception, have been characteristically associated with squamoid structures known as morules. By contrast, all reported non-neoplastic lesions with such inclusions lacked morules and were confined to pregnancy-related endometrium. In the present study, adding unreported types of morule-associated neoplastic lesions, we investigated the distribution of biotin, biotin-binding enzymes, and beta-catenin in these lesions by immunohistochemical staining. We detected the intranuclear localization of biotin and of two mitochondrial biotin-binding enzymes (pyruvic acid carboxylase and propionyl CoA carboxylase) in all lesions examined, regardless of whether they were neoplastic or non-neoplastic and irrespective of the presence or absence of morules. The intranuclear localization of beta-catenin was detected in all neoplastic lesions with morules and in ovarian endometrioid adenocarcinoma without morules, but not in non-neoplastic endometrial lesions. These results suggest the following conclusions: (1) lesions with biotin-rich intranuclear inclusions can be classified as non-neoplastic/pregnancy-related endometrial and as neoplastic/pregnancy-unrelated or morular category; (2) the intranuclear biotin in both types of lesion is found in conjunction with biotin-binding enzymes. However, the role of beta-catenin in morule-associated neoplastic lesions, the relationship between beta-catenin and biotin/biotin-binding enzymes, and the mechanism of migration of biotin and biotin-binding enzymes from the cytoplasm to the nucleus remain unclear.

Sentinel lymph node biopsy is performed as a standard procedure in breast cancer surgery, and the development of quick and simple methods to detect metastatic lesions is in high demand. Here, we validated a new fluorescent method using γ-glutamyl hydroxymethyl rhodamine green to diagnose metastatic lymph nodes in breast cancer. One hundred and forty-nine lymph nodes from 38 breast cancer patients were evaluated in this study. Comparison of fluorescent and pathological images showed that this fluorescent method was successful for visualizing breast cancer cells in lymph nodes. This method had a sufficiently high sensitivity (97%), specificity (79%) and negative predictive value (99%) to render it useful for an intraoperative diagnosis of cancer. These preliminary findings suggest that this novel method is useful for distinguishing non-cancerous specimens from those in need of careful examination and could help save time and cost for surgeons and pathologists.

We describe seven cases of melanotic oncocytic metaplasia of the nasopharynx and review five other cases in the literature. It is usually a small, brown to black lesion that occurs around the Eustachian tube opening, where abundant seromucinous glands and lymphoid tissue are present. Multiple or bilateral lesions are sometimes seen. All 12 reported cases are of Asian origin. Melanotic oncocytic metaplasia occurs predominantly in men (male:female=11:1), with a mean age of 68 years. Simple excisional biopsy appears to be curative. Microscopically, melanotic oncocytic metaplasia is a combination of oncocytic metaplasia of the epithelium of the gland and melanin pigmentation in its cytoplasm. Fontana-Masson staining and immunohistochemical staining of S-100 protein revealed numerous melanocytes with conspicuous dendrites in the glands and stroma, which probably transfer melanin to adjacent glands. The exact pathogenesis of melanotic oncocytic metaplasia is unknown, but we postulate that the lesion could be related to the oncocytic metaplasia of the seromucinous glands around the Eustachian tube, which is followed by the local production and/or acquisition of the melanin pigment, under the influence of certain neuropeptides in the vicinity. The recognition of melanotic oncocytic metaplasia is of clinical importance, as it may be misdiagnosed as a malignancy to the unwary.

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Myxoid adrenal cortical adenoma is a rare tumor and, to our knowledge, only 16 cases have been reported. We present the case of a 56-year-old Japanese man who was admitted to hospital because of a right adrenal mass that was discovered during a routine physical examination. The resected mass was well circumscribed and contained canary yellow multinodular regions that were surrounded by a brown gelatinous region. Histologically, the multinodular regions resembled a conventional adrenal cortical adenoma, being composed of solid aggregates of large clear or eosinophilic cells. In the gelatinous region, anastomosing small eosinophilic or vesicular cells were visible within a myxoid stroma that contained large amounts of acidic mucopolysaccharides. Light-microscopic findings were consistent with a diagnosis of adenoma. Immunohistochemical staining revealed that a small number of tumor cells were positive for vimentin, and the MIB-1 labeling index was less than 1%. Flow cytometry demonstrated that cells were diploid. At the ultrastructural level, many fat droplets were found in the large clear cells in the multinodular regions. Small eosinophilic cells in the myxoid region contained many mitochondria but few fat droplets. There were no findings suggestive of malignancy. Although the adrenal cortex might have the potential to produce connective tissue-type mucin as a consequence of its mesodermal origin, the mechanism of production of acidic mucopolysaccharides in a myxoid adrenal cortical tumor remains to be clarified.