Akira Tsutsumi

Tissue engineering skin flaps: which vascular carrier, arteriovenous shunt loop or arteriovenous bundle, has more potential for angiogenesis and tissue generation?

This study was designed to clarify which vascular carrier, the arteriovenous shunt loop or the arteriovenous bundle, has more potential as a vascular carrier for an artificial skin flap in rats. An arteriovenous shunt loop was constructed between the femoral artery and vein using an interpositional artery (group I) or vein (group II) graft. For arteriovenous bundle groups, the femoral artery and vein were used and subdivided into two groups: distal ligation type (group III) and flow-through type (group IV). The vascular pedicle was wrapped with an artificial dermis and implanted beneath the inguinal skin for 4 weeks. For the control group, a folded sheet of artificial dermis without any vascular carrier was embedded. In experiment 1, the volumes of generated tissue within the artificial dermis were measured in the experimental and control groups (n = 5 in each group). In experiment 2, the origin of new blood vessels sprouting from the arteriovenous shunt loop and arteriovenous bundle were evaluated histologically. The volume of generated tissue in the shunt groups was significantly greater than that in the bundle groups (p < 0.01). However, the bundle groups also showed a great potential for producing new tissue. Serial histological studies showed that new capillaries were derived not only from the vasa vasorum of the femoral vessels but directly from the femoral vein in both the shunt and the bundle groups. This “sprouting” was extensively exhibited in the group III. Although the arteriovenous shunt loop showed a greater potential for producing new tissue and capillaries, the distal ligation type of bundle was thought to be an effective and practical vascular carrier for producing a tissue-engineered skin flap.

Prefabricated engineered skin flap using an arteriovenous vascular bundle as a vascular carrier in rabbits

Background: The authors previously described induction of spontaneous tissue generation by implanting a collagen matrix and a ligated pedicle (arteriovenous bundle) into a hollow porous chamber in vivo in the rabbit. They hypothesized that increased tissue volume could be obtained by the application of basic fibroblast growth factor (bFGF) and/or by increasing the chamber size and porosity. Methods: In rabbits, a saphenous arteriovenous pedicle and a collagen sponge were inserted into a porous chamber in the groin. Small-volume pore chambers (experiment 1, n = 7) and larger-volume, wider pore chambers (experiment 2, n = 13) were compared, and each was compared with and without bFGF. An additional three flaps of experiment 2 with bFGF were skin grafted, microsurgically transplanted to the ear, and evaluated at 6 months for stability. Results: All patent chambers grew tissue; chambers with bFGF were almost filled, and those without were only half-filled. Histomorphometric analysis confirmed a significant difference. The larger-volume, larger-pore chambers produced more than twice the volume of tissue as the smaller chambers did, and this was significant. Tissue volume in both the control and bFGF groups of experiment 2 was significantly greater than that in the respective groups of experiment 1. Histology, angiography, and scanning electron microscopy confirmed greater vascularity in the bFGF groups and demonstrated vascular connections penetrating the chamber pores linking with angiogenic sprouts, probably from the vasa vasorum of the pedicle, to contribute to new growth. Transplanted flaps survived and appeared normal 6 months later. Conclusions: Patent pedicles, bFGF, large pore size, and larger-volume chambers all seemed to contribute to increased tissue growth in this model. The tissue is stable long term.

Duct‐acinar‐islet cell tumor of the pancreas

A case of a rare pancreatic tumor, duct‐acinar‐islet cell tumor is presented. The tumor was incidentally found in the pancreatic body on computed tomography of a 21 year old male suffering from mumps. It was well demarcated from surrounding pancreas, and spherical in shape, measured 2.5 cm in diameter. Histologic and immunohistochemical examinations showed the tumor to consist of three distinct cell populations: duct, acinar and islet cells. Small cell nests consisting of these cellular components, either solely of one cell type or mixed of the three cell types, were separated by broad desmoplastic stroma. Islet (endocrine) cells, which were most predominant, were arranged in a tra‐becular pattern or small cell nests. Most of them were positive for glucagon, and a few cells expressed insulin, somatostatin, serotonin or pancreatic polypeptide. These cells were distributed randomly within the cell nests. Ducts, some of which contained goblet cells, were found among the endocrine cell nests. Duct‐islet complexes were also observed. The acinar cells were the least conspicuous component. They expressed pancreatic α‐amylase. An electron microscopic examination revealed duct cells with intercellular attachments and interdigitations, endocrine cells containing secretory granules, and acinar cells with zymogen granules. No definite evidence suggesting malignancy could be obtained.

Cystic lymphoepithelial lesions of the pancreas and peripancreatic region: Report of two cases

Two cases of an extremely rare cystic lymphoepithelial lesion of a lymph node associated with the pancreas are presented herein. The first patient was a 57-year-old woman with a serous cystoadenoma who underwent resection of the body and tail of pancreas, and the other patient was a 75-year-old woman with cancer of the papilla of Vater who underwent pylorus-preserving pancreatoduodenectomy. Both lesions were incidentally found during pathologic examination of lymph nodes from the peripancreatic region. Histologically, there were many scattered nests of the lymphoepithelial lesion in the lymphoid stroma, each of which was lined with stratified squamous epithelium. The pathological structure was found to resemble the lymphoepithelial lesion of the pancreas. Although the histogenesis is unknown, we hypothesize that the lesion might have arisen from squamous metaplasia of a benign epithelial inclusion such as the pancreatic duct of an ectopic pancreas in a peripancreatic lymph node. Therefore, a cystic lesion formed as a result of keratinization of the squamous epithelium with invasion into the pancreas could become a lymphoepithelial cyst of the pancreas.

Symptomatic Hypertrophic Pacchionian Granulation Mimicking Bone Tumor

OBJECTIVE AND IMPORTANCE Osteolytic lesions can be seen in various diseases, and they also resemble the markings normally found on the cranium. We present a rare case of symptomatic hypertrophic pacchionian granulation mimicking bone tumor in the calvaria. CLINICAL PRESENTATION A 46-year-old woman suffered from a small hump accompanied by pain in the right frontoparietal region. A plain radiograph revealed two punched-out lesions. Precontrast-enhanced computed tomographic scans demonstrated hypodense masses, with partial defect of the outer table of the cranium. Magnetic resonance imaging demonstrated hypointense masses in the T1-weighted image and hyperintense masses in the T2-weighted image, with capsule-like contrast enhancement by gadolinium diethylenetriamine penta-acetic acid. INTERVENTION The masses were totally resected with attached bone and dura. One of them had destroyed the outer table of the cranium. The affected portions of the masses lacked the dura and partially adhered to the brain surface. Histologically, hypertrophic pacchionian granulation was diagnosed. CONCLUSION The patient has had no recurrence for 2 years. This case suggests the need to include hypertrophic pacchionian granulation in the differential diagnosis of punched-out lesions.

Xanthoma of the temporal bone: case report.

OBJECTIVE AND IMPORTANCE Xanthomas of the cranium that are not accompanied by endocrine or metabolic abnormalities are extremely rare. It is very important to understand the pathological features of this disease, for differential diagnosis from other diseases. CLINICAL PRESENTATION A 62-year-old woman presented to the hospital with headaches. Cranial x-rays revealed bone destruction in the right temporal bone, with osteosclerosis in the area surrounding the lesion. In computed tomographic scans, the bone cortex was intact and the diploë was dilated because of the large mass of the lesion. T1-weighted magnetic resonance imaging findings were heterogeneous, with areas of hypo- and isointensity; T2-weighted magnetic resonance imaging findings were also heterogeneous, with areas of hypo- and hyperintensity. INTERVENTION Total removal of the tumor was performed, followed by cranioplasty using artificial bone. DIAGNOSIS Histologically, lipid-containing foamy cells were dense and a cholesterin granuloma was observed. There was no reason to infer other diseases, and a diagnosis of xanthoma of the temporal bone was reached. CONCLUSION Xanthomatous lesions are observed in various pathological conditions, including malignant diseases. Xanthomas are benign lesions and the prognoses for patients with these lesions are satisfactory, even after partial excision. Therefore, it is quite important to distinguish xanthomas from other diseases that produce xanthomatous lesions.

Malignant pilocytic astrocytoma in the medulla oblongata: case report

A 27-year-old woman visited our hospital with chief complaints of abducens nerve palsy and cerebellar symptoms. On computerized tomographic scanning and magnetic resonance imaging, a tumor with strong enhancement was found on the dorsal side of the medulla oblongata. A tumor was excised by suboccipital craniotomy and C1 laminectomy. Histologically, many Rosenthal fibers together with pilocytic tumor cells were found in some regions, but a very high Ki-67 labeling rate accompanied by cells with nuclei of irregular size and giant cells was observed in other regions. The tumor was diagnosed as malignant pilocytic astrocytoma originating from pilocytic astrocytoma by transformation. The biological behavior of pilocytic astrocytoma is obscure in several respects. We report our experience of a case of malignant pilocytic astrocytoma that developed in the brain stem and progressed extremely rapidly.

Epithelioid hemangioendothelioma with osteoclast-like giant cells

Epithelioid hemangioendothelioma is an unusual entity of intermediate malignant vascular tumors and rarely admixes with multinucleated osteoclast-like giant cells. We describe such a case in a 50-year-old woman with an 1-year follow-up period. When the patient was 39 years old, a 0.7 x 1-cm firm mass was found in the left neck. She developed ascites three years later. At that time, the specimen from the neck mass was excised and found to be composed of cords of epithelioid cells in a myxoid hyaline stroma. Scattered intracytoplasmic vacuoles were seen. Immunohistochemical studies confirmed the diagnosis of epithelioid hemangioendothelioma. Abdominal ultrasonography and computed tomographic scan revealed multiple low density areas in the liver. Eleven years later, a metastatic lesion was found in the thoracic spine at the level of Th7-8. The histologic findings were basically similar to those of the left neck mass. However, because of the presence of Kp-1-positive multinucleated osteoclast-like giant cells throughout the tumor, the thoracic lesion was diagnosed as an epithelioid hemangiothelioma with osteoclast-like giant cells. This unique form of epithelioid hemangioendothelioma is extremely rare and should be distinguished from other benign and malignant tumors with osteoclast-like giant cells.

A cellular variant of supratentorial hemangioblastoma.

Supratentorial hemangioblastomas are rarely seen, especially in children and adolescents. We report the case of a 17-year-old male with supratentorial hemangioblastoma. Neuroimaging demonstrated a cystic lesion within the right parietal lobe. Systemic examination revealed no abnormality. The lesion was not attached to the dura and was not associated with von Hippel-Lindau disease. It was very difficult to confirm the final diagnosis of this case, in spite of extensive examination by light microscopy, immunohistochemical studies, and electron microscopy.

Ectopic arachnoid granulomatosis: a case report.

BACKGROUND Arachnoid granulation can sometimes show hypertrophy, developing extensively apart from the venous sinus, and in that case, a differential diagnosis should be made between this granulation and tumors. In this case, we hypothesized that cerebrospinal fluid was absorbed in the region of abnormal stains revealed by angiography. CASE DESCRIPTION A 67-year-old female with headache was admitted to our hospital. A plain radiograph revealed accumulated numerous osteolytic lesions in the right frontal bone. T1-weighted magnetic resonance (MR) images demonstrated mixed-intensity lesions. On the T2-weighted MR images, we observed that the lesions were mixed, with areas of the same intensities as gray matter and cerebrospinal fluid. An abnormal vascular stain from the frontal branch of the middle meningeal artery was confirmed. After a craniotomy, numerous white granular masses were observed. These masses had penetrated the dura mater and adhered rigidly to the arachnoid membrane. Histological examination revealed them to be normal arachnoid granulations and villi. CONCLUSION This case was diagnosed as an ectopic arachnoid granulomatosis. No case report has previously been published describing numerous arachnoid granulations away from the venous sinuses.