Atypical lipoma, atypical intramuscular lipoma, and well differentiated retroperitoneal liposarcoma: a reappraisal of 30 cases formerly classified as well differentiated liposarcoma

Thirty cases formerly diagnosed as Grade I lipogenic liposarcoma (well differentiated liposarcoma) were reviewed. The basic histologic pattern in all was that of adult fat modified by the presence of cells with enlarged, hyperchromatic nuclei; in most cases there was also a component of myxoid and/or fibrous tissue. The length of follow-up ranged from two to 30 years. Nine of the tumors were located in the subcutaneous layer. None of these recurred after excision, not even those which were simply "shelled out," and none metastasized. The term "atypical lipoma" is proposed for this group. Thirteen were located within or between muscles of the limbs, limb girdles, and head and neck. Nine of these recurred at least one, but there were no metastases and no deaths due to tumor. These were designated "atypical intramuscular lipoma." The remaining eight originated in the retroperitoneum. Although none of these patients developed metastases, five suffered inoperable recurrence and three died as a result of the neoplasm. It is suggested that the term "well differentiated retroperitoneal liposarcoma" be retained for cases of this type.

Association of islet cell carcinoma of the pancreas with subcutaneous fat necrosis

A 57-year-old man with generalized, subcutaneous fat necrosis was found at autopsy to have islet cell carcinoma of the pancreas. The histologic diagnosis of islet cell carcinoma was confirmed by the finding by electron microscopy of characteristic intracytoplasmic granules within pancreatic neoplastic cells. Lipase levels were elevated in serum as well as in tissues in areas of subcutaneous fat necrosis. Enzyme histochemical stains for alkaline and acid phosphatase, leucine, aminopeptidase, succinic dehydrogenase, and indoxyl and nonspecific esterase were positive in the areas of subcutaneous fat necrosis. This is the first report of the association of islet cell carcinoma of the pancreas with generalized subcutaneous fat necrosis.

Behavioral assessment of visual toxicity

A wide variety of behavioral methods has been employed with animals to assess visual changes induced by drugs or toxicants. The methods range from simple to complex, from broad screening devices to narrowly focused techniques. Their relative advantages for the environmental toxicologist are discussed. Manipulation of stimulus values is an essential ingredient in the identification of specific sensory functions. The percentage of correct choices from a discrete-trial, multiple-choice discrimination procedure is to be preferred to measures of response rate, speed or reaction time when experiments require answers about specific visual functions.

Malignant lymphoma, small lymphocytic type: a clinicopathologic study of 84 cases with suggested criteria for intermediate lymphocytic lymphoma

Clinical and histopathologic findings were reviewed in 84 cases of malignant lymphoma of the small (well differentiated) lymphocytic type. The slides were studied without clinical information, and the following morphologic features were evaluated: pattern of growth, number of large lymphocytes, mitotic rate, degree of capsular involvement, presence of plasma cells and/or plasmacytoid lymphocytes, and presence of residual germinal centers. Subsequently, clinical information was obtained. The minimum follow-up period on living patients was 5 years. The patients were divided into 3 clinical categories: 1) monoclonal gammopathy (MG)-11 cases, 2) chronic lymphocytic leukemia (CLL) without MG-56 cases, and 3) those without MG or CLL at the time of lymph node biopsy-17 cases. The criterion for CLL was an initial absolute lymphocyte count less than 4000/mm3. Four of the patients with MG also had CLL, and 6 of those in the third group later developed CLL, from 1 to 61 months after lymph node biopsy. Generalized lymphadenopathy was the usual presentation in all 3 groups, and bone marrow examination was positive in all but 1 of the 49 cases, representing all 3 groups, in which it was performed. Median survival for the 84 patients was 51 months. The only clinical parameters which showed a significant association with poorer survival were age above 60 and anemia (Hb. conc. less than 11.0). There was no significant relationship between morphologic characteristics and clinical categories other than the association of plasmacytoid cells with MG in 6 cases. A mitotic rate of 30 or more mitoses per 20 high power fields (HPF), found in 5 cases with at least 1 in each clinical category, showed a highly significant association with decreased survival (p = .01). Variations in mitotic rate between 0 and 29 mitoses per 20 HPF and other morphologic parameters did not show a significant relationship with prognosis. It was concluded that malignant lymphoma of the small lymphocytic type is a definite clinicopathologic entity which may or may not exhibit MG or CLL, and it is proposed that the term "intermediate lymphocytic lymphoma" be applied only to those cases showing histopathologic characteristics of small lymphocytic lymphoma and a mitotic rate of 30 or more mitoses per 20 HPF.

Unusual gonadal stromal tumor of the testis. Case report with ultrastructural observations

Ultrastructual observations on an unusual gonadal stromal tumor of the testis in a 4-year-old boy with gynecomastia revealed that the tumor cells lacked the abundant smooth endoplasmic reticulum usually found in neoplastic and nonneoplastic Sertoli and Leydig cells. The cells were rich in cytoplasmic microfilaments, with localized dense areas of the type seen in smooth muscle cells as well as intracytoplasmic lipid droplets. It is concluded that the tumor cells show important similarities to the immature fusiform interstitial cells and the peritubular contractile cells present in the normal testis.

Scopolamine effects on visual discrimination: modifications related to stimulus control

Stumptail monkeys (Macaca arctoides) performed a discrete trial, three-choice visual discrimination. The discrimination behavior was controlled by the shape of the visual stimuli. Strength of the stimuli in controlling behavior was systematically related to a physical property of the stimuli, luminance. Low luminance provided weak control, resulting in a low accuracy of discrimination, a low response probability and maximal sensitivity to scopolamine (7.5--60 mug/kg). In contrast, high luminance provided strong control of behavior and attenuated the effects of scopolamine. Methylscopolamine had no effect in doses of 30 to 90 mug/kg. Scopolamine effects resembled the effects of reducing stimulus control in undrugged monkeys. Since behavior under weak control seems to be especially sensitive to drugs, manipulations of stimulus control may be particularly useful whenever determination of the minimally-effective dose is important, as in behavioral toxicology. Present results are interpreted as specific visual effects of the drug, since nonsensory factors such as base-line response rate, reinforcement schedule, training history, motor performance and motivation were controlled. Implications for state-dependent effects of drugs are discussed.

Behavioral effects of mercury and methylmercury

Intoxication by elemental mercury or by methylmercury is revealed primarily by changes in behavior and by neurological signs. Disorders of movement and posture have been most widely reported, both in animal experiments and in cases of human exposure. Specific sensory symptoms are also prominent in human methylmercury poisoning. Recent data indicate similar symptoms in monkeys during long-term exposure to methylmercury. Similar sensory impairment has not been described in experiments with subprimates. Variations in the profile of behavioral and neurological effects are discussed in terms of differences in species and differences between acute and long-term exposure. The latter condition poses the most difficult questions for human health, yet has been less frequently studied. Procedures are suggested that may help to revolve these problems. In particular, tests of learned behavior hold great promise toward identifying specific symptoms and toward understanding how mercury compounds affect behavior.

Alkylmercurial encephalopathy in the monkey (Saimiri sciureus and Macaca arctoides): a histopathologic and autoradiographic study

Histopathologic and autoradiographic studies were performed on monkeys of the genera Saimiri and Macaca after acute and chronic oral exposure to several dosage regimens of methylmercuric chloride (MeHg). Neuropathologic changes were primarily cortical, although subcortical lesions also were observed. Autoradiographic localization of 203-Hg was greatest within glial cells (particularly Nissl-pump astrocytes, subependymal glia and Bergmann's glia) and mast cells. High levels of label within normal appearing large neurons (particularly those within Gasserian and dorsal root ganglia) indicate a lower susceptibility of these neurons to the toxic effects of MeHg. Blood and brain levels of mercury correlated well with the degree of neuropathologic change, but individual variations in susceptibility to intoxication also existed.