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If the tumor is bilateral, it is almost always seen in a VHL patient. The tumor destroys the mastoid air spaces and extends into the middle ear and/or posterior cranial fossa. [1] [3] A high power image of an endolymphatic sac tumor showing clear cytoplasm in cuboidal cells lined up along papillae.
Pneumoperitoneum is pneumatosis (abnormal presence of air or other gas) in the peritoneal cavity, a potential space within the abdominal cavity.The most common cause is a perforated abdominal organ, generally from a perforated peptic ulcer, although any part of the bowel may perforate from a benign ulcer, tumor or abdominal trauma.
In perineural invasion, cancer cells proliferate around peripheral nerves and eventually invade them. Cancer cells migrate in response to different mediators released by autonomic and sensory fibers. Tumor cells secrete CCL2 and CSF-1 to accumulate endoneurial macrophages and, at the same time, release factors that stimulate perineural invasion.
On abdominal x-ray, stomach GISTs may appear as a radiopaque mass altering the shape of the gastric air shadow. Intestinal GISTs may displace loops of bowel and larger tumors may obstruct the bowel and films will show an obstructive pattern. If cavitations are present, plain radiographs will show collections of air within the tumor. [22]
The presacral space may contain one of several kinds of tumor. The most common tumor here is sacrococcygeal teratoma. Others are retrorectal hamartoma (tailgut cyst), schwannoma, ganglioneuroma, and ependymoma. Also sometimes found here is an anterior meningocele, a relatively mild form of neural tube defect.
One study has shown extra-abdominal tumors making up 43% of cases, abdominal tumors 49%, and mesenteric 8%, though statistics vary. [16] Pregnancy-related tumors typically arise in the abdominal wall. [28] Tumors located intra-abdominally or in the head and neck have the highest risk of mortality due to the proximity to vital structures. [20]
Tumor cells describe irregular tubular structures, harboring pluristratification, multiple lumens, reduced stroma ("back to back" aspect). Sometimes, tumor cells are discohesive and secrete mucus, which invades the interstitium producing large pools of mucus. This occurs in mucinous adenocarcinoma, in which cells are poorly differentiated.
The Pancoast tumor was first described by Hare in 1838 as a "tumor involving certain nerves". [2] It was not until 1924 that the tumor was described in further detail, when Henry Pancoast, a radiologist from Philadelphia, published an article in which he reported and studied many cases of apical chest tumors that all shared the same radiographic findings and associated clinical symptoms, such ...