Signet-ring cell carcinoma of the gallbladder: a case report.

Gallbladder cancers are recognised common tumours of the gastrointestinal system. Histologically, almost all of them are adenocarcinomas. Previously, only two cases of signet-ring cell carcinoma of the gallbladder have been published, and little is known about the disease.

Renal parenchymal malacoplakia: a different stage of xanthogranulomatous pyelonephritis?

Malacoplakia is a rare inflammatory condition characterized by demonstrative Michaelis-Gutmann bodies, which are foamy histiocytes with distinctive basophilic inclusions. Malacoplakia is caused by the inadequate elimination of bacteria by macrophages or monocytes as a result of defective phagocytic activity. Xanthogranulomatous pyelonephritis is characterized by the destruction of renal parenchyma and its replacement by solid sheets of foamy lipid-laden macrophages.

Malignant eccrine poroma invading the parotid gland.

Malignant eccrine poroma was first described by Pinkus and Mehregon in 1963. Because of the histologic characteristics of the tumor, these authors concluded that the tumor was likely of eccrine origin. Malignant eccrine poroma originates from the intraepidermal ductal portion of the eccrine gland.