Biomedical subjects
Publications and source records attributed to J Lloreta.
The ultrastructural appearance of an endometrial stromal nodule with prominent smooth and skeletal muscle differentiation is described. This is the first reported case of endometrial stromal nodule with a heterologous skeletal muscle component and emphasizes the value of electron microscopy and its correlation with immunohistochemistry in the study of rare or complex lesions.
A 28-year-old man presented with left cervical lymph node metastases and a 7-cm mass in the left lobe of the liver. Biopsy material from both sites revealed a fibrolamellar hepatocarcinoma (FLHC) with immunocytochemical and ultrastructural evidence of neurosecretory differentiation. The patient refused treatment. He died 6 years after the onset of symptoms with grade IV coma and bilateral bronchopneumonia. Postmortem examination disclosed persistent neoplastic disease in the liver and left lateral cervical lymph nodes as well as widespread deposition of AA amyloid in tumor stroma and in blood vessel walls of many tissues but mainly in the kidney, gastrointestinal tract, and heart. This appears to be the first report documenting the association of FLHC and amyloid deposition in the English literature.
A case of epithelial mesothelioma presenting as an axillary metastasis of unknown origin with anemone cells in a 33-year-old patient with pleural effusion is reported. The differential diagnosis included tumors that can be composed of cells with anemone shape (malignant lymphoma, leukemia, malignant melanoma, carcinoma, and mesothelioma). Tumor cells in the present case were positive for cytokeratins (Cam 5.2 and AE1/3) as well as vimentin antibodies and were consistently negative for carcinoembryonic antigen, Leu-M1, leukocyte common antigen, pan-B-cell and pan-T-cell antigen, Ber-H2, S-100 protein, HMB-45, and epithelial membrane antigen antibodies. On electron microscopy, the most remarkable features were the presence of abundant, long, slender microvilli, the lack of well-developed intercellular junctions, and only occasional tight junctions in some of the tumor cells. A pleural needle biopsy confirmed the pleural origin of the proliferation. The patient refused treatment and died 3 years after diagnosis.
A case of polymorphous low-grade adenocarcinoma arising in the right nasal cavity of a male patient with previous history of kidney transplantation is reported. The tumor contained extensive areas of undifferentiated carcinoma, probably arising from the low-grade component. This combination of findings has not been previously reported in this variety of salivary gland tumor.
The ultrastructural features of a case of severe hyperthyroid myopathy are presented. Along with the moderate increase in mitochondrial size and number usually observed in most patients with hyperthyroid myopathy, some of the skeletal muscle mitochondria in the present case also contained paracrystalline rectangular inclusions. This finding has not been previously reported in hyperthyroid myopathy and further supports the current view that mitochondrial abnormalities play a major role in the pathogenesis of muscle dysfunction in hyperthyroid patients.
There is increasing evidence that exercise overload induces changes in skeletal muscle structure and function. Recent studies suggest that muscle mitochondria could be involved either as the result or the origin of these changes. This study describes a case of a patient with marked air flow obstruction related to chronic obstructive pulmonary disease, in which large aggregates of mitochondria were found in diaphragm muscle fibers. Many of the mitochondria contained paracrystalline rectangular inclusions. Latissimus dorsi and intercostal muscles were also available for ultrastructural examination that showed, respectively, normal and moderately increased number of mitochondria with normal mitochondrial structure. This is the first known report of paracrystalline rectangular inclusions in respiratory skeletal muscle from a patient with chronic obstructive pulmonary disease.
Ultrastructural and morphometric features of 10 medullary carcinomas of the breast (MC) were investigated. Cases with a long follow-up were selected by applying stringent histologic criteria. All tumors had a homogeneous appearance by light microscopy. Under transmission electron microscopy, they showed occasional intracellular lumen formation or keratinization. In one tumor squamous differentiation was prominent and diffuse. Tumors with lymph node metastases possessed over 40% more desmosomes than nonmetastatic tumors. The number of cells with three or more nucleoli per nuclear section was significantly higher in metastatic than in nonmetastatic tumors (p = .02). Classic cases of MC of the breast display a relatively uniform appearance. However, subtle differences can be identified between metastatic and nonmetastatic tumors by ultrastructural morphometry. Although these differences are not associated with changes in the outcome of patients in this study, they seem to bear some relationship to the peculiar behavior of MC.
The authors report the light microscopic and ultrastructural features in one case of malakoplakia involving the kidney, the urinary bladder, and the skin. The kidney was excised. Lesions of the urinary bladder and the skin regressed after topical treatment with cholinergic agonists and antimicrobial drugs. This case illustrates the pathogenesis of malakoplakia and the possibility that early lesions can be cured with medical therapy before extensive tissue destruction has taken place.
The authors report a renal cell carcinoma composed largely of spindle cells of Fuhrman's nuclear grade II in which the bland appearance of the cells and low mitotic index were reminiscent of a benign or low-grade smooth muscle tumor. Keratin immunostaining was positive, but evidence of epithelial differentiation was obtained by electron microscopy. The tumor was an incidental finding and it did not invade the perirenal fat or the renal vein. Follow-up is only 24 months but the histological features suggest that the prognosis may be better than that of a classic sarcomatoid renal cell carcinoma.
The clinicopathologic, immunocytochemical, and electron microscopic features of a case of meningeal melanocytoma arising in the phylum terminale are reported. Meningeal melanocytoma is an uncommon tumor that must be distinguished from metastatic or primary malignant melanoma, meningeal melanocytic nevi, pigmented meningioma, pigmented schwannoma or neurofibroma, and pigmented primitive neuroectodermal tumor. This is a difficult differential diagnosis that can be best archived by complementing histological examination with a selected panel of antibodies and, most important, electron microscopic study. The distinctive ultrastructural appearance of most of these lesions point to this technique as the gold standard in pigmented proliferations of the nervous system.