Congenital pseudarthrosis of long bones: a clinical, radiographic, histologic and ultrastructural study.

Sixteen patients with pseudarthrosis of the tibia and one of the radius were evaluated clinically, radiograpically, and microscopically and separated into 3 groups; 8 had neurofibromatosis clinically, 3 had fibrous dysplasia histologically, and 6 had no evidence of either neurofibromatosis or fibrous dysplasia. Prognosis and therapy were determined by correlated clinical, radiographic, and histological observations. Fracture before age 2 years carried a poor prognosis. Electron microscopy allowed neither differentiation among these fibrous lesions, nor any clue to their origin, nor did it support the concept of a neural or vascular derivation.     

Peripheral medulloepithelioma: an immunohistochemical,ultrastructural, and cytogenetic study of a rare,chemotherapy-sensitive,pediatric tumor

A case of peripheral medulloepithelioma, a rapidly growing tumor involving the pelvic cavity of a 12-year-old girl, is presented. The diagnosis was supported by expression of vimentin, nestin, alpha-internexin, neurofilaments, and microtubule-associated protein 5 and by characteristic ultrastructure that included absence of cilia or microvilli. Trisomy of chromosomes 2 and 8 was the only detectable chromosomal abnormality. Combination chemotherapy resulted in complete remission. Because some of these rare tumors are sensitive to chemotherapy, their recognition and separation from other neuroectodermal tumors are advisable for better understanding of their biology and determination of optimal treatment.     

Atypical inflammatory histiocytic tumor of the cerebellum. A histological, immunohistochemical, and ultrastructural study

We report a primary histiocytic tumor involving the cerebellum. Microscopically, the tumor was composed of nests of pleomorphic cells surrounded by thin vascular septa invaded by lymphocytes. Immunocytochemistry and electron microscopy confirmed the histiocytic origin of the tumor. Although we considered several diagnoses, we ultimately concluded that "atypical inflammatory histiocytic tumor of the cerebellum" best characterized the lesion. This case represents another example of the diversity of histiocytic tumors and shows that they can occur in the central nervous system.     

Plantar fibromatosis: an immunohistochemical and ultrastructural study

The analogies between plantar fibromatosis and Dupuytren's disease (palmar fibromatosis) are well known. The latter is clinically more frequent and has been the object of extensive immunohistochemical and ultrastructural studies, with a view to investigating its pathogenesis. By contrast, such data on plantar fibromatosis are quite scarce. A histochemical, immunohistochemical, and ultrastructural study was performed on nodule tissue from six patients who were subjected to total fasciectomy for plantar fibromatosis. The study of myofibroblasts revealed features suggestive of their fibroblastic origin and evidenced a cytoskeleton and an extracellular filamentous system that could enable myofibroblasts to generate and exert the intracellular forces that contribute to the contraction of the aponeurosis. These aspects are similar to those observed in Dupuytren's disease and seem to lend support to the theory that the two diseases are expressions of the same disorder.     

Benign fibroblastic polyps of the colon: a histologic, immunohistochemical, and ultrastructural study

Mesenchymal proliferations presenting as mucosal polyps are relatively uncommon and are represented by gastrointestinal stromal tumors, smooth muscle and neural tumors, and inflammatory fibroid polyps. In this report, we describe the clinicopathologic features of a distinctive type of mucosal polyp composed of cytologically bland spindled cells with fibroblastic features. Fourteen cases with histologic features of"fibroblastic polyps" were identified from our case files from January 2000 to December 2003. The clinical and endoscopic findings were reviewed. Immunohistochemistry using a panel of antibodies (vimentin, smooth muscle actin, desmin, CD31, CD34, Bcl-2, c-Kit, S-100, and epithelial membrane antigen) was performed in all cases, and electron microscopy was performed in two cases. The lesions were solitary in all cases and not associated with an identifiable polyposis syndrome. Associated adenomata and/or hyperplastic polyps at different sites were present in 10 cases and hyperplastic polyps were seen in close association in 3 cases. These polyps were characterized by a monomorphic spindle cell proliferation in the lamina propria, without necrosis or mitotic activity. The lesions were intimately associated with the muscularis mucosae and resulted in wide separation and disorganization of the colonic crypts. Immunohistochemical analysis revealed strong and diffuse positivity for vimentin only. Weak and focal reactivity was noted in 2 cases for CD34 and smooth muscle actin, while staining for other antibodies was negative. Electron microscopy revealed sparse cytoplasmic organelles and many intermediate filaments. The histology and ultrastructural and immunohistochemical findings are suggestive of fibroblastic differentiation of these spindle cells. In summary, these lesions represent a distinctive type of colonic mucosal polyp that should be distinguished from other stromal polyps of the gastrointestinal tract.     

Intraventricular solitary fibrous tumor: an unusual tumor with radiological, ultrastructural, and immunohistochemical evaluation: case report

OBJECTIVE AND IMPORTANCE: Intracranial solitary fibrous tumors have been described previously, but intraventricular solitary fibrous tumors are extremely rare. We present what is, to our knowledge, the first reported case of solitary fibrous tumor in the third ventricle. CLINICAL PRESENTATION: A 63-year-old man presented with weakness of his lower extremities and headaches. Computed tomography and magnetic resonance imaging of the brain revealed an enhancing mass in the posterior part of the third ventricle. INTERVENTION: The tumor originated from the wall of the left internal cerebral vein and extended to the posterior part of the third ventricle. Nearly total excision was performed via an infratentorial-supracerebellar approach. CONCLUSION: The differential diagnosis of intracranial solitary fibrous tumors includes fibroblastic meningioma, meningeal hemangiopericytoma, neurofibroma, and schwannoma. The differential diagnosis in the present case was greatly helped by the immunohistochemical and ultrastructural findings, along with a disease-free 3.5-year follow-up. These findings are presented with reference to previous reports.     

Congenital macrodactyly: a clinical study

Congenital macrodactyly is a rare congenital malformation characterised by progressive enlargement of all mesenchymal elements of a digit. The present study is an attempt to draw the attention towards the similarities and differences between macrodactyly of the hand and foot. Radiographical, operative findings and histopathological examination of five cases are included in the present study. Emphasis was given to know the possible basic lesion. Radiographic findings, which differentiate this entity from other forms of local gigantism, were also analysed. The most characteristic finding noted was excessive overgrowth of fibro-fatty tissue with unusually large fatty lobules, apparently fixed by a mesh of dense fibrous tissue. Hypertrophy and tortuosity of the digital nerve, a striking feature in macrodactyly of the hand, was notably absent in cases affecting the foot. None of the patients had any other associated congenital anomalies. Neither the patients nor any of their family members had any stigmata of neurofibromatosis. Chromosomal study was normal in all of them. We conclude that in macrodactyly of the foot, excessive proliferation and accumulation of adipose tissue was the basic lesion, whereas involvement of the nerve might be the fundamental lesion in gigantism of the hand. Furthermore, whatever be the basic lesion, the final pathway must be either the local deficiency of a growth inhibiting factor or local expression of a basic intrinsic factor, leading to excessive growth of all elements of the digit.     

Primary bone leiomyosarcoma. Anatomo-clinical, immunohistochemical, and ultrastructural study

A variety of tissues in bone can be the origin of neoplastic primitive lesions. Consequently, it can be the site of various sarcomas of tissue type, incursing leiomyosarcoma. The leiomyosarcoma of the bone is considered as primitive after exclusion either a bony extension of a soft tissue tumor of vicinity or the presence of a leiomyosarcoma elsewhere. We report a case of a primary leiomyosarcoma arising on the left femur of a 40-year-old woman. The diagnosis was confirmed by immuno-histochemistry and electron microscopic study. A bloc resection followed by a prothesis was performed. The patient underwent a fractioned postoperative radiotherapy with a total dose of 75 Gy. The postoperative course one year later revealed local recurrence and pulmonary metastases. Despite the resection of pulmonary metastases and the amputation of left lower limb, the patient had developed local recurrence on the stump of amputated limb and was on the outside of all therapeutic resource. In this report, we present the clinicopathologic, immuno-histochemical and ultrastructural profiles of these rare primary bone tumors.     

Nesidioblastosis arising from heterotopic pancreas and presenting with hypertension. A clinical, immunohistochemical and ultrastructural study

A rare case of nesidioblastosis in an adult arising from heterotopic pancreas and presenting with hypertension is reported. To our knowledge it is the first case to be described in literature. The pathogenic mechanisms to explain hypertension are not clear. The stimulating action of glucagon on the adrenal gland or on peripheral beta receptors could be considered as hypothetical factors.     

Myofibroblasts in adolescent varicocele: an ultrastructural and immunohistochemical study

Myofibroblasts of the testes play an important role in the morphofunctional integrity of the seminiferous tubule. Previous studies in adults with varicocele have demonstrated an involvement of this cell population that tends to transform into fibroblasts. The aim of the present study was to try and verify the morphological features of myofibroblasts in the adolescent with left idiophatic varicocele. Twenty-two testicular biopsies were obtained from adolescents (aged 13–18 years, mean 15.8) and operated for left idiophatic varicocele. Biopsies were processed for electron microscopy (TEM) and immunofluorescence studies. The latter determined the level of myofibroblasts by using α-smooth muscle isoactin, a specific marker of myofibroblasts and, hence, excluding fibroblasts. TEM observations revealed a normal ultrastructure of myofibroblasts that was similar to that for the controls but an increased presence of extracellular matrix. The immunofluorescence study always demonstrated strong cell positivity to anti α-smooth muscle isoactin as also seen in the controls. This study demonstrates that adolescents with varicocele have well preserved myofibroblasts and do not show any evidence of transformation into fibroblasts, this has already been demonstrated in adult varicocele. These observations could represent an important factor for the understanding of the reversal of growth failure of the testes observed after early treatment. Received: 22 February 1999 / Accepted: 21 July 1999     

Clear cell tumor of the lung. A clinicopathologic, immunohistochemical, and ultrastructural study of eight cases.

We studied eight clear cell tumors of the lung (CCTL) to better define their clinical, immunohistochemical, and ultrastructural features, and to clarify their distinction from other neoplasms, particularly metastatic renal cell carcinoma. Patients ranged in age from 31 to 67 years (mean, 51 years). Seven patients had clinically benign, asymptomatic lesions measuring less than 2 cm in diameter that were devoid of necrosis. The eighth patient had a symptomatic, partially necrotic CCTL 4.5 cm in diameter that metastasized to the liver and peritoneum; the patient died of tumor 17 years after diagnosis. Ultrastructural study of seven CCTL showed interdigitating cell processes (all cases), primitive cell junctions (five of seven cases), intracytoplasmic glycogen (all cases), and rare dense core granules (two of seven cases). Immunohistochemically, paraffin-embedded sections from all eight CCTL were negative for cytokeratin (CK), epithelial membrane antigen (EMA), chromogranin, and vimentin. Focal staining was seen for S-100 protein (three of eight cases), neuron-specific enolase (three cases), synaptophysin (one case), and Leu 7 (one case). Although these findings suggest that at least some CCTL exhibit neuroendocrine differentiation, the tumor's histogenesis remains uncertain. Of more practical importance, the combined absence of CK, EMA, and vimentin in formalin-fixed, paraffin-embedded CCTL virtually precludes confusion with renal cell carcinoma. Although traditionally considered benign, CCTL larger than 2 cm that are symptomatic, and focally necrotic should be regarded as potentially malignant neoplasms.     

Proliferative myositis. An immunohistochemical and ultrastructural study

We studied four cases of proliferative myositis by the avidin-biotin-peroxidase complex technique, using a panel of 12 antibodies, and by electron microscopy. The aim was to clarify the nature of their constituent cells, specifically the giant ganglion-like cells and spindle cells, and to discuss the implications for histogenesis. In all cases, both cell types showed positive cytoplasmic staining with antibodies to vimentin, actin (C4), and alpha-smooth muscle actin-1, but in only one was there positive staining with desmin. No staining was obtained with factor XIIIa, muramidase, alpha-1-antitrypsin, myoglobin, S-100 protein, CAM 5.2, factor VIII-related antigen, or neuron-specific enolase. By electron microscopy, both types of cells were seen to contain numerous thin filaments, dense bodies, coated and pinocytotic vesicles, active and dilated rough endoplasmic reticulum, few microvilli, and incomplete desmosomal junctions. Our findings imply a myofibroblastic nature for the giant ganglion-like cells and spindle cells. Our observations also support the hypothesis that they are derived from a pericytic cell.     

Primary synovial sarcomas of the mediastinum: a clinicopathologic, immunohistochemical, and ultrastructural study of 15 cases

A series of 15 cases of primary mediastinal neoplasms displaying histopathologic, immunohistochemical, and ultrastructural features of synovial sarcoma is presented. The patients' ages ranged from 3 to 83 years, with a male-to-female ratio of 2:1. Nine cases presented as anterior mediastinal masses with chest pain, shortness of breath, and pleural effusion, and 6 cases were in paravertebral location in the posterior mediastinum and presented with neck or back pain and pleural effusion. The tumors measured from 5 to 20 cm in greatest diameter and showed a tan white, soft to rubbery cut surface with areas of hemorrhage and necrosis and foci of gelatinous material. Four cases showed areas of cystic degeneration. In 7 cases, the tumors were well circumscribed; in 6 cases, the tumors grossly invaded the pleura, pericardium, heart, great vessels, chest wall, rib, and vertebra. Histologically, 5 cases displayed a biphasic growth pattern, with well-formed glandular elements admixed with a monotonous spindle cell population. Ten cases were exclusively composed of a monotonous atypical spindle cell proliferation. Immunohistochemical studies showed focal positivity of the tumor cells for cytokeratin and/or epithelial membrane antigen, and strong positivity for vimentin and bcl-2 in the spindle cells in all cases studied (10 of 10). Eight cases also showed focal positivity for CD99. Electron microscopic examination in 5 cases showed oval to spindle tumor cells with closely apposed cell membranes, abundant cytoplasmic intermediate filaments and rough endoplasmic reticulum, and immature desmosome-type cell junctions. Ten patients were treated by complete surgical excision and two by partial excision followed by radiation therapy. In 4 patients, the tumors were inoperable and treated with radiation therapy only. Clinical follow-up was available in 5 patients and showed local recurrence with metastases to lung, lymph nodes, and epidural space from 1 to 3 years in 4 cases and liver metastases and death due to tumor after 6 month in 1 case. Synovial sarcoma should be considered in the differential diagnosis of biphasic and monophasic spindle cell neoplasms of the mediastinum.     

Primary pulmonary paraganglioma: report of a functioning case with immunohistochemical and ultrastructural study

We describe a case of primary pulmonary paraganglioma, a tumor that has not been reported in sufficient detail in previous literature. The patient was a 55-year-old woman with hypertension accompanied by an elevated serum norepinephrine level (2651 pg/mL; normal 100-450 pg/mL). Computed tomography revealed a well-circumscribed solid mass, 3.5 cm in diameter, located in the lower lobe of the left lung. In the lobectomy specimen, the tumor had invaded the B8 bronchus and hilar lymph nodes with microscopic metastasis to the mediastinal nodes. The tumor showed histologic, immunohistochemical, and ultrastructural features of paraganglioma: argyrophilic cells arranged in a nesting (Zellballen) or anastomosing trabecular pattern within an arcuate vascular network. Neoplastic chief cells positive for neuroendocrine markers (CD56, synaptophysin, chromogranin A) were surrounded by sustentacular cells positive for S-100 protein. Neurofilament protein was positively stained, but cytokeratins were totally negative. On electron microscopy, chief cells possessed abundant dense core granules with an eccentric halo ("norepinephrine-type" granules). The patient's blood pressure began to decline soon after the resection, and her serum norepinephrine promptly returned to almost normal. On the basis of our experience, our case is a bona fide primary pulmonary paraganglioma, a tumor heretofore subject to considerable skepticism.     

Male breast cancer: clinical, pathologic and immunohistochemical study

Forty-three cases of male breast cancer treated in the past 3 decades, comprising 1.92% of total cases of breast cancer in both sexes during the same period, were analyzed. Local skin involvement occurred in half of the patients. 67.7% of the patients presented axillary lymph node metastases and 82.9% were in stage II and III. Non-infiltrative and infiltrative specific cancers were diagnosed in 2 cases each, and infiltrative non-specific in 39 cases. Retrospective determination of estrogen receptor (ER) and carcinoembryonic antigen (CEA) in 33 specimens revealed positive ER in 57.6% and positive CEA in 72.7%. The more advanced the clinical stage, the higher is the positive rate of ER. Cases with positive CEA usually carried a more invasive process and a poorer prognosis. Immunohistochemical investigation in male breast cancer patients was valuable in the selection of post-operative adjuvant endocrine therapy or chemotherapy. Postoperative rise in serum CEA in patients with positive CEA may indicate recurrence.     

Epithelioid hemangioendothelioma of bone. A clinicopathologic, ultrastructural, and immunohistochemical study

In a review of 29 cases of solitary and multicentric hemangioendothelial sarcomas of bone, 14 were found to have histologic features of epithelioid hemangioendotheliomas. These were characterized by the presence of epithelioid or "histiocytoid" endothelial cells that were either round or spindle-shaped. Intracytoplasmic vacuolization was noted, and some showed nesting of cells, mimicking metastatic adenocarcinoma. The presence of a myxoid matrix suggested the diagnosis of chondrosarcoma in some cases. Some of the tumors strongly resembled the lesions formerly designated as intravascular bronchioloalveolar tumor, angioglomoid tumor of bone, or malignant myxoid angioblastoma of bone. Factor VIII-related antigen was detected in five of the six cases examined, and ultrastructural study in five cases confirmed the endothelial nature of the tumor cells; Weibel-Palade bodies were present in three cases. There were 11 men and three women, and the tumors were seen predominantly in patients who were under 30 years of age (10 cases). Four cases involved solitary tumors, and nine were multicentric in bone. The multicentric tumors had a predilection for the bones of one lower extremity (five cases). The total series had a protracted clinical course, and the multicentric tumors appeared to follow a less aggressive course.