Tomohiko Kizaki

Solitary fibrous tumor in the extremity: case report and review of the literature.

A solitary fibrous tumor is a relatively unusual neoplasm first described as a distinctive tumor arising from pleura. Some reports have shown that solitary fibrous tumors also affect extrathoracic regions. The current study presents a literature review with four additional patients with solitary fibrous tumor arising from the extremities to clarify clinicopathologic features. The current four patients were two males and two females, ranging from 17 to 60 years of age. Magnetic resonance imaging scans of the current patients showed inhomogeneous low to intermediate intensity signal on T1-weighted images and inhomogeneous intermediate to high intensity signal on T2-weighted images. Histologically, the tumors were composed of a haphazard proliferation of spindle cells, although cellularity was variable in each case. Two of the four tumors showed hypercellularity of spindle cells with focally myxomatous or hyaline changes, whereas myxomatous patterns with scattered spindle cells throughout the specimens were observed in the other two tumors. Immunohistochemically, all four patients showed positive immunoreactivity for CD34, and two tumors showed focally positive immunoreactivity for bcl-2 protein. During the followup of 12 to 54 months, neither local recurrence nor distant metastasis was detected after wide resection. Examination of the literature and the current patients suggests that solitary fibrous tumors in the extremities are likely to have a malignant potential, although most patients have a benign clinical course. Local wide resection and careful long-term followup are necessary for patients with solitary fibrous tumor in the extremities.

Expression of matrix metalloproteinases, tissue inhibitors of metalloproteinase, collagens, and Ki67 antigen in pleural malignant mesothelioma : an immunohistochemical and electron microscopic study

Because matrix metalloproteinases (MMPs) degrade extracellular matrix, including basement membrane, and because tissue inhibitors of MMP (TIMPs) suppress MMP activities, MMPs and TIMPs are considered to play important roles in invasion and metastasis in many malignancies. We examined immunohistochemically the expression of MMPs (MMP-1, -2, -3, -7, and -9), TIMPs (TIMP-1 and -2), and collagens (types I, III, and IV) in 16 patients with pleural malignant mesothelioma (PMM; 8 with the epithelial, 4 with the sarcomatous, and 4 with the biphasic type). Electron microscopy revealed that the tumor cells in all types possessed the characteristics of malignant mesotheliomas, including numerous microvilli and moderate amounts of intermediate filaments. Basement lamina was present only focally. The proliferative Ki67 index was at a high level, compared with values reported in various other malignancies. Positive staining for MMP-1 was observed in most tumor cells in all 16 patients (100%). MMP-2 was expressed in most tumor cells in 2 patients (13%). In contrast, MMP-3, -7, and -9 were not detected in any PMM. TIMP-1 and TIMP-2 were expressed in 3 patients (19%) and 2 patients (13%), respectively. The stromal cells were simultaneously positive for MMPs or TIMPs in the patients whose tumor parenchymal cells were positive for each enzyme. These results indicate that the expression of MMP-1 and MMP-2 may be related to PMM invasion and spread. In particular, as MMP-1 was overexpressed in contrast to the lower expression of TIMP-1, MMP-1 is strongly suggested to play an important role in PMM invasion by degrading the tumor stroma. In spite of general agreement that epithelial-type PMM has a better prognosis than other types, there was no significant difference in the Ki67 index among the histological types of PMM.

Neural fibrolipoma of the superficial peroneal nerve in the ankle: A case report with immunohistochemical analysis

This report presents a case of neural fibrolipoma arising from the superficial peroneal nerve in the ankle. A 28‐year‐old woman was referred with a soft tissue mass in the anterior aspect of the right ankle, which had been gradually enlarging for the past 10 years. Magnetic resonance imaging showed a mass lesion, measuring approximately 8 × 3 × 2 cm, with high to partially low signal intensity on both T1‐ and T2‐weighted images. A band of low signal intensity within the lesion, which is indicative of coexistence with the tumor and the superficial peroneal nerve, could be detected on both T1‐ and T2‐weighted images. The patient underwent an excisional biopsy. The specimen microscopically consisted of nerve bundles and fibro‐fatty proliferation with abundant collagen fibers. Immunoreactivity for CD34 antigen antibody was detected in fibrous spindle cells. This is the first report to present an immunohistochemical profile of neural fibrolipoma. Neural fibrolipoma should be considered as a differential diagnosis when a lipomatous lesion is encountered in the foot or ankle as well as in the upper extremities.

Leiomyosarcoma arising from soft tissue tumor of the mediastinum

 The occurrence of a leiomyosarcoma (LMS) in soft tissue of the mediastinum is rare. We report a 60-year-old woman with an LMS in mediastinal soft tissue who died 8 months after surgical removal. Pathological, immunohistochemical, and electron microscopic features of this rare tumor are described.

Synovial sarcoma arising from the pleura: a case report with ultrastructural and immunohistological studies.

 Synovial sarcoma commonly occurs in the para-articular regions of the extremities, and rarely in the pleura. We report a 46-year-old woman with primary synovial sarcoma of the pleura. She was admitted with a complaint of left-sided chest pain and exertional dyspnea. She had previously undergone two operations for pleural neoplasm, at the ages of 33 and 36 years. A computed tomography scan revealed an expanded mass in the left thoracic cavity, involving the surrounding tissue. Macroscopic findings demonstrated a 25 × 25 × 15-cm grayish-white mass with hemorrhage beneath the pleura. Both epithelial and spindle cells were observed microscopically. Ultrastructural microscopy of the epithelioid cells demonstrated short, blunt microvilli on the luminal surface, and desmosomes between the neoplastic cells. Immunohistochemically, the tumor cells of the epithelial component were positive for embryonal membrane antigen (EMA), carcinoembryonic antigen (CEA), human mesothelial cells (HBME)-1, and cytokeratin, and the spindle cells were positive for vimentin. These findings led us to a diagnosis of primary synovial sarcoma of the pleura. She had no evidence of recurrence or metastasis after the third operation.

Renal adenomatosis associated with carcinoma of the lower urinary tract: A case report with immunohistochemical study

A case of renal adenomatosis of the left kidney associated with a carcinoma of the ipsilateral ureter in a 49‐year‐old man is examined. One hundred and eight adenomas, which were smaller than 15 mm in diameter, and a single microcarcinoma, which measured 1 mm in diameter, were found in the kidney. Further, there were more than 800 hyperplastic lesions which could be classified into three groups: (i) 792 of distal origin; (ii) 24 of proximal origin; and 10 of collecting duct origin. The serial sections obtained from 19 paraffin blocks were stained using Leu M1 as the proximal marker and epithelial membrane antigen (EMA) as the distal/ collecting marker to assist in determining the origins. Ten of the small adenomas (15 lesions), which did not exceed 3 mm in diameter, were predominantly positive for EMA and five were predominantly positive for Leu M1. Further, hyperplastic lesions of distal and collecting duct origins were diffusely positive for EMA and sporadically positive for Leu M1. The lesions of proximal origin were predominantly positive for Leu M1 and sporadically positive for EMA. These findings suggest that a progression from hyperplasia and a direct transition from a single tubule to adenoma occurred multifocally in different segments of the nephrons throughout the left kidney.

Histochemical Analysis of Changes in Lectin Binding in Murine Glomerular Lesions

Lectin binding in diseased murine glomeruli was studied in MRL 1 mice, using seven different fluorescence‐ or peroxidase coupled lectins: Griffonia simplicifoliaI (GS‐I), Ulex europaeusagglutinin I (UEA‐I), Ricinus communisagglutinin I (RCA I), wheat germ agglutinin (WGA), concanavalin A (Con A), peanut agglutinin (PNA), andHelix pomatia agglutinin (HPA). Lectin binding in diseased glomeruli of MRL 1 mice was different from that in normal glomeruli. Light and fluorescence microscopy showed that: 1. in mesangial proliferative lesions, the binding of RCA I, WGA and Con A increased and that of GS I and PNA appeared in the mesangium; 2. in other glomerular lesions, UEA‐I bindng appeared and RCA I stained the altered membranes irregularly. Electon microscopy showed that: 1. GS‐I stained the endothelial cell coat and the glomerular basement membrane covered by the endothelial cells; 2. GS I strongly stained the dilated subendothelium in regions of mild mesangial interposition; 3. GS‐I stained the cell coat of invasive macrophages; 4. GS‐I and UEA‐I stained the cell membrane‐like material derived from degenerative endothelial cells; 5. RCA I stained the epithelial and endothelial cell coats and the glomerular basement membrane. These results indicate that lectin‐binding studies can be used for analysis of glomerular lesions.

Malignant mesothelioma of the pericardium: case reports and immunohistochemical studies including Ki-67 expression.

Pericardial malignant mesothelioma (PMM) is extremely rare compared with pleural cases of mesothelioma. We present the clinical and pathological features of three autopsy cases with PMM. All three cases showed rapid progress and died of heart failure. Detailed examination was obtained from the autopsy. Macroscopic appearances of each case showed a thickened pericardium due to tumor invasion. Microscopic observations of all cases led to a diagnosis of epithelial‐type malignant mesothelioma (MM). The results of immunohistochemical examinations were similar to the previous published work on pleural mesothelioma. To disclose the pathological characteristics of PMM, we analyzed Ki‐67 labeling index (LI) of three cases of PMM and five cases of pleural MM that died within 2 years. The difference of Ki‐67 LI between PMM and pleural MM was not significant (P > 0.05). The poor prognosis of patients with PMM must be caused by restricted cardiac wall motion due to tumor involvement, in addition to the tumor proliferation itself.

Pulmonary tumor thrombotic microangiopathy showing aggressive course after transurethral resection of urinary bladder: an autopsy case report

A 77-year-old man developed pulmonary tumor thrombotic microangiopathy (PTTM) 2 days after undergoing transurethral resection for urothelial carcinoma (G3) of the urinary bladder and died of respiratory failure 6 days later. Histological findings demonstrated marked intimal fibrocellular proliferation, fibrin thrombi, and both cancer cells and fibrin thrombi in the arteries of the lungs, findings consistent with PTTM. Prominent stenosis in arteries smaller than 300 μm was also seen. The Ki-67 labeling index of primary and metastasized cancer cells was 62.4 % and 70.2 %, respectively. The membranes of metastasized cancer cells expressed E-cadherin, similar to membranes in the urinary bladder. An aggressive PTTM course is affected by intimal fibrocellular proliferation and the high cell proliferation of cancer cells. Furthermore, prominent stenosis in small arteries and membranous staining of E-cadherin of metastasized cells suggest that cancer cells formed clusters by maintaining adhesion molecules and migrated into the arteries of the lungs, where they easily caused damage to the endothelium of small arteries, in contrast to dispersed cancer cells.

Anaplastic osteosarcoma with abundant eosinophilic cytoplasm and minimal osteoid production

A case of osteosarcoma with unusual microscopic features, occurring in the right proximal tibial metaphysis of a 12‐year‐old boy is reported. Radiographically, the tumor was ill‐defined and purely osteolytic. On gross examination, the tumor was soft, fragile, spongy and red to brown in color. Microscopically, the tumor consisted of pleomorphic cells possessing abundant eosinophilic cytoplasm, including cells larger than 100 μm in diameter. The cells were arranged in a sheet, with few extracellular collagen fibers. Multiple sectioning of the specimens revealed a small amount of osteoid production. Immunohistochemical study revealed a positive reaction for vimentin and osteocalcin. Electron microscopic study suggested the fibroblastic or osteoblastic origin of the cells.