Edmondo Govoni

Pathological Study of the Sural Nerve in Fabry’s Disease

A man with Fabrys disease, who died at 52, suffered from lancinating limb pains between the age of 20 and 27, and from severe arthralgia between 20 and 40. The sural nerve showed a severe loss of fibers (1,614 myelinated fibers/mm2), chiefly affecting the small myelinated fibers. Inclusions of both homogeneous and lamellated appearance were present in the perineurial cells, fibroblasts and vessel walls. Teased fibers displayed moderate remyelination, regeneration and the presence of globular focal myelin thickening. The transient time course of painful manifestations in this case is stressed in view of a possible pathogenesis of pain in Fabrys disease. It appears that small-fiber neuropathy is not directly related to the occurrence of pain symptoms, since the prevalent loss of small myelinated fibers was seen in the absence of actual pain. The small sensory neurons in the dorsal root ganglia, that are especially affected by lipid accumulation, probably give rise to abnormal discharges producing pain via the prevalence of the small-fiber versus the large-fiber input to the dorsal horn of the spinal cord (gate control theory). Thus pain fits may spontaneously abate, as in our case, if degeneration and loss of the small sensory neurons overstep a critical level.

Signet ring cell lymphoma: A case report

The authors report a case of signet ring cell lymphoma, a rare variety of germinal (follicular) centre cell neoplasm. Its clinical, histological and ultrastructural findings are compared with those of the nine cases previously described. Original immunocytochemical results are presented and discussed.

Ultrastructural and immunohistochemical contribution to the histogenesis of human cardiac myxoma.

The ultrastructural features of 8 human cardiac myxomas were analyzed and correlated with immunohistochemical data, with the aim to clarify the characteristics of the cell lines involved in the tumor genesis. Immunohistochemical studies were performed to detect the presence and the distribution of intracytoplasmic filaments (vimentin, desmin, actin, myosin) as well as myoglobin and factor VIII-related antigen, albumin, and lysozyme. Eighty percent of myxoma cells were simultaneously positive for vimentin, desmin, and actin, whereas 30% of them stained with antifactor VIII and antivimentin antibodies. The submicroscopic analysis revealed two main cell populations: (1) one composed of stellate-shaped cells with scanty organelles and sparse hyaloplasmic filaments scattered throughout the myxoid stroma and forming a loose network with their projections; (2) another one included cells with more cytoplasmic organelles, intermediate filaments, and myofilaments arranged either singly or in both solid and hollow cord-like structures. Our results support the hypothesis that cardiac myxoma may originate from a reserve multipotent mesenchymal cell able to differentiate more or less completely along two major evolutional lines: myoid and endothelial. The tumor tissue thus seems to be involved in vessel formation, suggesting a growth pattern akin to that manifested in other forms of endocardial pathological reactivity in which reserve mesenchymal cells are engaged.

A 48-hour preservation of an isolated human uterus: endometrial responses to sex steroids *

Human uteri were perfused with Krebs-Ringer bicarbonate-glucose buffer with and without estrogens and progesterone for a period of up to 48 hours to preserve a viable organ, which was responsive to hormones. Flow rates of 12 to 35 ml/minute per artery were fully distributed into the organ, with pressure values ranging from 80 to 120 mm Hg. Arteriovenous gradients of oxygen and carbon dioxide tensions as well as the levels of lactate, lactic dehydrogenase, and creatine kinase released in the perfusate, indicators of tissue ischemia or cell necrosis, showed a good preservation of the organ for up to 48 hours. The light- and electron-microscopic examinations of endometrial and myometrial tissues taken before and during perfusion confirmed this result. The extracorporeal perfusion of uteri with buffer containing estrogens plus progesterone exhibited secretive modifications of the proliferative endometrium, thus suggesting the viability of the organ and its responsiveness to sex steroids.

Sclerosing stromal tumor of the ovary - A hormonal, histochemical and ultrastructural study

Three new cases of sclerosing stromal tumor of the ovary have been studied by hormonal, immunohistochemical and electron microscopic analysis. The results confirm that this tumor may have hormonal activity. Ultrastructural study shows findings different from those previously reported. The authors propose an origin from the ovarian stroma with luteinization of stromal tumor cells.

Polyneuropathy in Progressive External Ophthalmoplegia

A case of progressive external ophthalmoplegia (PEO) in association with peripheral neuropathy and other neural and visceral manifestations is reported. Pathological studies of the sural nerve demonstrated loss of large myelinated fibers, segmental demyelination with remyelination, and excess of zebra bodies in the Schwann cells on electron microscopy. Peripheral neuropathy in the course of PEO is regarded as a further although rare aspect of a multisystem disease.

Primary malignant fibrous histiocytoma of the spleen: an ultrastructural study.

A primary malignant fibrous histiocytoma of the spleen was studied by light and electron microscopy and is believed to be the first reported. The neoplasm was predominantly fibroblastic, with a characteristic storiform pattern, and included histiocyte‐like cells, giant and foam cells confirmed by ultrastructural studies. Additionally, undifferentiated cells, intermediate cells and myofibroblasts were seen. The differential diagnosis from other sarcomas and the histogenesis of this tumour are discussed.

Anaplastic type of medullary thyroid carcinoma

A case of anaplastic type of medullary thyroid carcinoma is presented. Immunoperoxidase study revealed calcitonin within the tumor cells, which also showed argyrophilia. At ultrastructural examination the tumor also displayed mucoid and squamous differentiation. This multidirectional differentiation (endocrine and exocrine) underlies the difficulty of ascribing a precise histogenesis to this tumor.

Report of a case of non-Hodgkin's lymphoma of large multilobated cell type with B-cell origin

Large multilobated nuclei lymphoma is a rare entity that is characterized morphologically by large neoplastic elements with prominent nuclear lobations and clinically by a predilection for extranodal sites and a favorable prognosis. According to the data collected to date, the neoplasia is thought to be of T-cell origin. The authors describe the clinical, morphologic and immunohistochemical findings of a case of non-Hodgkins lymphoma with large multilobated nuclei that showed a definite B-lymphocyte origin.

Ependymoma of the Foramen of Monro: Ultrastructural Characterization

The characteristics of clear cells of an ependymoma of the foramen of Monro have been studied by electron microscopy to precisely define its organellar composition and to establish the tumor histogenesis. Our data confirm that the once-thought oligodendroglial is, in fact, an ependymal tumor. Both the scarce number of organelles, owing to the low degree of differentiation, and the abundance of hyaloplasmic lipid vacuoles can account for the clear appearance of these tumor cells.