Fig. Artist illustrations of the synovial sheaths and bursae of the wrist and hand, with the distribution of a horseshoe abscess extending along the radial and ulnar bursae.
Pseudomyxoma peritonei is a condition where the peritoneal cavity is filled with thick gelatinous mucous from a mucous secreting tumour, commonly from the appendix, ovary, stomach or pancreas. Due to the pressure of the thick secretions, oscillating indentations are seen in the liver and spleen which resemble the curves in the scallop shell. This was first described in pseudomyxoma by Parikh et al in 1987. 1 .Pseudomyxoma peritonei is an uncommon clinical entity with an estimated incidence of one to two per million per year. It is characterized by diffuse intra-abdominal gelatinous collections with mucinous implants on peritoneal surfaces and the omentum. The long-term survival is poor with reported 5 and 10 year survival rates of 50% and 10%-30%, respectively. 2 In men, pseudomyxoma peritonei predominantly originates from a perforated appendiceal mucinous tumour. Increasingly evidence suggests most cases in females also arise from appendiceal mucinous tumours (based on immuno-histochemistry and molecular genetic techniques). 2 One study showed that scalloping of the liver (demonstrated on ultrasound) had a sensitivity of 88% and a specificity of 42%. The lower specificity was due to the sign also being seen in other peritoneal malignancies (such as metastatic ovarian carcinoma). This study found that anechoic areas within the thickened peritoneum (and omentum) was the most specific sign for pseudomyxoma peritonei. The anechoic areas represented mucinous nodules within the cellular material. 3 Related signs • Scalloping o Scalloping: various signs in the chest o Endosteal scalloping: pattern of bone erosion • Ascites o Dog ears appearance: ascites o Mickey Mouse Signs References 1. Parikh V, Jain C, Desai M. CT of pseudomyxoma peritonei. Am
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