Granular Cell Tumors of the Abdominal Wall

Granular cell tumors (GCT) are found in virtually any body site, including the tongue, skin, subcutaneous tissue, breast, rectum and vulva. However, they are rarely seen in the abdominal wall. We report here on a rare case of GCT in the rectus muscle of the abdominal wall. A 44-year-old woman presented with a non-tender, hard mass in the right lower abdominal wall. Upon microscopic examination, the tumor was found to comprise of large polygonal cells with an abundant eosinophilic granular cytoplasm and round to oval nuclei. Upon immunohistochemical staining, the large cells showed S-100 and CD68 positive granular aggregates in the cytoplasm. Many lysosomes of variable size were observed in the cytoplasm.

Granular Cell Tumors of the Abdominal Wall

Granular cell tumors (GCT) are found in virtually any body site, including the tongue, skin, subcutaneous tissue, breast, rectum and vulva. However, they are rarely seen in the abdominal wall. We report here on a rare case of GCT in the rectus muscle of the abdominal wall. A 44-year-old woman presented with a non-tender, hard mass in the right lower abdominal wall. Upon microscopic examination, the tumor was found to comprise of large polygonal cells with an abundant eosinophilic granular cytoplasm and round to oval nuclei. Upon immunohistochemical staining, the large cells showed S-100 and CD68 positive granular aggregates in the cytoplasm. Many lysosomes of variable size were observed in the cytoplasm.

Morphometry and Histochemistry of the Rectus abdominis Muscle Fibers of Tufted Capuchin Monkeys (Cebus apella Linnaeus, 1758) / Morfometría e Histoquímica de las Fibras del Músculo Recto del Abdomen del Mono Capuchino Almohadillado (Cebus apella Linnaeus, 1758)

The phylogenetic proximity of primates to humans, along with their behavioral, biochemical, and anatomical similarities, make such animals more interesting experimental models for biomedical researches, as compared to classical laboratory animals. Another aspect that has called the attention of researchers is the differentiated quadrupedalism present in some primates. The tufted capuchin monkey uses the ground and tree branches as its support for locomotion, showing various postures while performing this task. On the basis of this information, we have decided to study the rectus abdominis muscle of the tufted capuchin monkey, with the following goals: the frequency and area of fiber types; its possible compartmentalization; and identify if this muscle is better adapted to phasic or postural activities. To do this, samples were removed from 4 regions of the rectus abdominis muscle of 6 adult male tufted capuchin monkeys, and were submitted to reaction with m-ATPase, (with alkaline and acid pre-incubation), NADH, and H.E.. Results showed: a statistically significant difference (P<0.05) for both frequency and area, between fiber types FG and FOG and FG and SO, but did not show a statistically significant difference between fibers FOG and SO, in all studied regions; similarity in frequency and area of a same fiber type (FG, FOG, and SO) among the studied regions. Based on these data, it was concluded that: the rectus abdominis muscle of the tufted capuchin monkey does not show fiber compartmentalization, since the distribution and size patterns of the different fiber types are similar in the studied regions; there is a predominance of fast twitch fibers (FG + FOG) over slow twitch fibers (SO), for frequency and area, which characterizes the muscle as being more dedicated to phasic than to postural activities.

La proximidad filogenética y las semejanzas de comportamiento, bioquímicos y anatómicos, de los primates con los humanos convierten a estos animales en modelos experimentales más interesantes para las investigaciones biomédicas, que los animales clásicos de laboratorio. Otro aspecto que ha llamado la atención de los investigadores es el movimiento cuádruple diferente que presentan algunos primates. El macado clavo se traslada usando como apoyo el suelo y las ramas de los árboles, presentando posturas variadas en la ejecución de esas tareas. En base a estas informaciones se resolvió estudiar el músculo recto del abdomen del macaco-clavo, con los siguientes objetivos: observar la frecuencia y el área de los tipos de fibras de este músculo; observar posibles diferencias entre e1las y sus regiones media proximal y distal; y su participación en la locomoción de este animal. Para ello, fueron retiradas 4 muestras de 4 regiones del músculo recto del abdomen, de 6 macacos-clavos machos adultos, que fueron sometidos a las reacciones de m-ATPasa (previa incubaciones alcalina y ácida), NADH y HE. Los resultados mostraron: diferencias estadísticamente significativas (p<0,05) tanto en la frecuencia como en el área, entre las fibras del tipo FG y FOG y FG y SO, pero no presentaron diferencias estadísticamente significativas entre las fibras FOG y SO, en todas las regiones estudiadas. Basándome en estos datos, se concluye que el músculo recto del abdomen del macaco-clavo no presenta división de sus fibras, pues los patrones de distribución y tamaño de los diferentes tipo de de fibras son semejantes en las regiones estudiadas con predominio de las fibras de contracción rápida (FG + FOG) sobre aquellas de contracción lenta (SO), tanto en la frecuencia como en el área, caracterizándolo como un músculo más adaptado para las actividades sutiles que posturales.

A comparative study of aging of the elastic fiber system of the diaphragm and the rectus abdominis muscles in rats

In the present study the age-related changes of the striated muscle elastic fiber system were investigated in the diaphragm and rectus abdominis muscles of 1-, 4-, 8- and 18-month-old rats. The activation patterns of these muscles differ in that the diaphragm is regularly mobilized tens of times every minute during the entire life of the animal whereas the rectus abdominis, although mobilized in respiration, is much less and more irregularly activated. The elastic fibers were stained by the Verhoeff technique for mature elastic fibers. Weigert stain was used to stain mature and elaunin elastic fibers, and Weigert-oxone to stain mature, elaunin and oxytalan elastic fibers. The density of mature and elaunin elastic fibers showed a progressive increase with age, whereas the amount of oxytalan elastic fibers decreased in both diaphragm and rectus abdominis muscles and their muscular fascias. These age-related quantitative and structural changes of the elastic fiber system may reduce the viscoelastic properties of the diaphragm and rectus abdominis muscles, which may compromise the transmission of tensile muscle strength to the tendons and may affect maximum total strength