A previously reported autopsy case of eosinophilic coronary periarteritis (ECPA, or isolated eosinophilic coronary periarteritis, IECPA), and an additional six autopsy cases of ECPA are reported. In addition, another four autopsy cases of ECPA reported in the literature are discussed. Fifteen cases of ECPA with spontaneous coronary dissection (hematoma), which appeared in the literature from 1987 to 2011, are also reviewed. The characteristic clinico-pathological findings of ECPA are: (a) variant angina (Prinzmetal's vasospastic angina) appeared mainly from evening to early in the morning; (b) allergy or allergic history could be identified in only three of a total of 11 cases; (c) sudden unexpected death (sudden cardiac death) usually occurred early in the morning; (d) eosinophilic inflammation limited to the adventitia and periadventitial soft issue appeared in the epicardial large coronary arteries, chiefly in the left coronary anterior descending artery; (e) fibrinoid necrosis or granuloma could not be found in or around the inflammatory area; (f) no type of vasculitis could be found in any other tissues or organs (i.e., localized and non-systemic periarteritis); (g) ECPA was frequently accompanied by spontaneous coronary arterial dissection (SCAD) in the affected wall; and (h) ECPA without SCAD appeared mainly in men (male/female ratio was 8:3), while EPCA with SCAD appeared in almost all female cases (male/female ratio was 1:14). Although the etiology and pathogenesis are still unknown, we believe that ECPA (with or without SCAD) might be a distinct new type of coronary arteritis.

Peripheral T-cell lymphoma, not otherwise specified (PTCL-NOS) consists of a heterogeneous group of lymphomas. Patients generally show an aggressive clinical course and very poor outcome. Although the 2008 World Health Organization classification of PTCL-NOS includes 3 variants, low-grade lymphoma is not included. Of 277 PTCL-NOS cases recorded in our consultation files, we examined the clinicopathologic characteristics of 10 patients with T-cell lymphomas composed of small-sized cells with slight nuclear atypia. Eight patients showed extranodal involvement (5 patients, spleen; 3 patients, thyroid), and 5 patients were at clinical stage I or II. Histologically, all samples presented diffuse infiltrate of small lymphoid cells, with few mitotic figures. Immunohistologically, all samples were positive for CD3, and CD20 was detected in 5 samples. All samples showed a low Ki-67 labeling index (mean, 1.05%), and 7 samples were positive for central memory T-cell markers. Clonal T-cell receptor γ chain and/or α-β chain gene rearrangements were detected in all 10 patients. Five patients received chemotherapy, whereas for 3 patients, treatment consisted only of observation following surgical resection of the spleen or thyroid. Nine patients were alive at a median follow-up time of 19.5 months, whereas 1 patient died of an unrelated disease. The present study strongly indicates that T-cell lymphoma with small-sized lymphoma cells and a low Ki-67 labeling index is a distinct variant. Recognition of this novel lymphoma subtype, which should not be defined merely as PTCL-NOS, should be seriously considered.

A carcinogenicity study of urethane was performed for quantitative assessment of Its risk in humans. Three hundred 6‐week‐old male B6C3F1 mice were divided into 6 groups, each consisting of 50 mice, and urethane was given ad libitum in drinking water at levels of 0 (control), 0.6, 3, 6, 60 and 600 ppm for 70 weeks. The tumors with a clear dose‐response relationship were lung tumor (alveolar/ bronchiolar adenoma or carcinoma) and liver tumor (hemangioma or angiosarcoma). The incidences of these two types of tumor were applied to estimation of the virtually safe dose (VSD) at the level of 10 6 by using four mathematical models (Logit, Probit, Weihull and Multistage models). The VSD based on the incidences of lung tumor by using the Logit model was estimated to be 1.8 × 10 4 mg/kg body weight/day. On the other hand the VSD based on those of liver tumor by using the Weibull model was 7.2 × 10−5 mg/kg body weight/day. Thus, the VSDs based on the incidences of the two different types of tumor using the most compatible mathematical model in each case, as judged from the P‐values, were similar.

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