Usefulness of KL-6 in the subtyping of intraductal papillary mucinous neoplasia of the pancreas, including carcinoma, dysplasia, and hyperplasia.

KL-6 is known as a useful serum biomarker of the disease activity in interstitial pneumonias. We investigated its usefulness as a biomarker for subtyping intraductal papillary mucinous neoplasms (IPMNs) of the pancreas. IPMNs are generally divided into 4 subtypes, namely pancreatobiliary (PB), intestinal (INT), gastric (GS), and oncocytic (ONC). Aside from the KL-6 antibody, the MUC1, MUC2, MUC5AC, MUC6, and MIB-1 antibodies were also examined. Eighteen IPMN cases were examined, including 12 cases of intraductal papillary mucinous carcinomas (IPMCs) simultaneously associated with dysplasia (IPMDs) and hyperplasia (IPMHs) and 6 IPMD cases with IPMH. KL-6 antibody was positive in the 8 IPMC cases, corresponding to a MUC2-negative PB subtype, but negative in 4 IPMC cases, corresponding to the INT subtype, which is positive for MUC2. IPMD of moderate-to-severe degree positively stained for the KL-6 antibody in the IPMC cases of the PB subtype but not in those of the INT subtype. The IPMH cases were mostly negative for KL-6, similar to the mild IPMD cases. In the 6 cases of mild IPMD and/or IPMH, KL-6 and MUC2 expressions were mostly negative. In conclusion, the KL-6 antibody is immunohistochemically a good biomarker of the PB subtype of IPMC, but not the INT subtype. Identifying IPMN subtypes based on KL-6 stainability would be useful. Clinicopathological studies with more IPMC cases might be needed for further progress in this field of study.

[Adenocarcinoma and basaloid squamous cell carcinoma in the same lung lobe].

We encountered a rare case of an adenocarcinoma and basaloid squamous cell carcinoma in the same lung lobe. The patient was a 66-year-old female. During the observation of the course of angina pectoris, chest computed tomography( CT) showed a nodular shadow in the right upper lung field and a club like lesion dorsal to this shadow. Since the former lesion was diagnosed as an adenocarcinoma, right upper lobectomy and lymph node dissection were performed. The latter lesion was diagnosed as a basaloid squamous cell carcinoma by pathology. Basaloid squamous cell carcinoma is a relatively rare tumor associated with a poor prognosis that is classified as a subtype of squamous cell carcinoma. There have been no reported cases of this tumor developing concurrently with adenocarcinoma. Since there were no histological transition images, and immunostaining findings completely differed between the 2 tumors, these tumors may have incidentally developed during the same period in the same lung lobe.

[Thymic mucosa-associated lymphoid tissue (MALT) lymphoma developing during long-term follow-up for Sjögren's syndrome and idiopathic thrombocytopenic purpura;report of a case].

Mucosa-associated lymphoid tissue (MALT) lymphoma is a rare type of lymphoma that arises in small CD20-positive lymphocytes. We encountered a case of thymic MALT lymphoma treated with surgical intervention during long-term follow-up for Sjögren's syndrome and idiopathic thrombocytopenic purpura (ITP). Although symptomatic remission of Sjögren's syndrome and ITP had already been achieved, the levels of anti-SSA and anti-SSB antibodies remained high. Chronic stimulation by these antibodies may contribute to the development of MALT lymphoma. A careful follow-up may be indicated for this case with a complex immunological background.

Pulmonary hypertension associated with diffuse deposition of pentosidine in pulmonary arterioles.

Diabetes induces advanced glycation end products (AGEs) that per se are not only a major cause of oxidative stress but also reduce the plasticity of connective tissue by pathological collagen cross-linking. We describe a case of severe pulmonary hypertension manifesting as a major diabetic complication. Impaired pulmonary arteriolar plasticity attributed to pentosidine, together with increased circulation volume by hyperosmotic pressure and reduction in myocardial compliance by multiple patchy fibrosis, may contribute to the clinical manifestation of severe pulmonary hypertension.

Immunohistochemical and electron microscopic studies of a case of duodenal gangliocytic paraganglioma.

Gangliocytic paraganglioma (GPG) is a rare tumor, occurring almost exclusively in the duodenum. In the present case, a submucosal tumor 2.5 x 2 x 1.5 cm in size was located on the anal side of the papilla of Vater, with clear margins and without capsule on cut-surface examination. Tumor cells included three types of cells: ganglion-like cells (GCs), endocrine cells (ECs), and Schwann cells (SCs). The GCs were large with eccentric nuclei with large nucleoli and clear abundant cytoplasm. ECs were detected in small nests, surrounded by bundles of SCs. Immunohistochemically, GCs were positive for synaptophysin, neuron-specific enolase (NSE), and CD56. ECs were positive for chromogranin A, NSE, somatostatin, pancreatic polypeptide, and CD56, and were associated with S100 protein-positive SCs. On fine structural examination, ECs contained numerous membrane-bounded secretory granules, 250-450 nm in diameter, in their cytoplasm, surrounded by a branched, complex basal lamina. SCs possessed basal lamina along their long interlacing cytoplasmic processes. The histogenesis of GPG most likely involves proliferation and differentiation of pluripotent stem cells in the duodenal crypts in the duodenum as a true tumor, although it is also possible that the retroperitoneal components of both GCs and SCs proliferate, together with ECs, from ventral primordial tissue of the pancreas in the duodenum. The immunohistochemical and ultrastructural findings of a case of GPG are reported, focusing on three major cellular components: GCs, ECs, and SCs.