The Myth of Fibroid Degeneration in the Canine Intervertebral Disc: A Histopathological Comparison of Intervertebral Disc Degeneration in Chondrodystrophic and Nonchondrodystrophic Dogs.

Since the seminal work by Hans-Jörgen Hansen in 1952, it has been assumed that intervertebral disc (IVD) degeneration in chondrodystrophic (CD) dogs involves chondroid metaplasia of the nucleus pulposus, whereas in nonchondrodystrophic (NCD) dogs, fibrous metaplasia occurs. However, more recent studies suggest that IVD degeneration in NCD and CD dogs is more similar than originally thought. Therefore, the aim of this study was to compare the histopathology of IVD degeneration in CD and NCD dogs. IVDs with various grades of degeneration (Thompson grade I-III, n = 7 per grade) from both CD and NCD dogs were used (14 CD and 18 NCD dogs, 42 IVDs in total). Sections were scored according to a histological scoring scheme for canine IVD degeneration, including evaluation of the presence of fibrocyte-like cells in the nucleus pulposus. In CD dogs, the macroscopically non-degenerated nucleus pulposus contained mainly chondrocyte-like cells, whereas the non-degenerated nucleus pulposus of NCD dogs mainly contained notochordal cells. The histopathological changes in degenerated discs were similar in CD and NCD dogs and resembled chondroid metaplasia. Fibrocytes were not seen in the nucleus pulposus, indicating that fibrous degeneration of the IVD was not present in any of the evaluated grades of degeneration. In conclusion, intervertebral disc degeneration was characterized by chondroid metaplasia of the nucleus pulposus in both NCD and CD dogs. These results revoke the generally accepted concept that NCD and CD dogs suffer from a different type of IVD degeneration, in veterinary literature often referred to as chondroid or fibroid degeneration, and we suggest that chondroid metaplasia should be used to describe the tissue changes in the IVD in both breed types.

Dermatoses do pavilhäo auricular / External ear dermatosis

Apresentamos uma atualizaçäo sobre as dermatoses que ocorrem no pavilhäo auricular. Propomos uma classificaçäo em sete grupos e realizamos uma sucinta descriçäo clínica de cada uma das 84 entidades catalogadas, de forma didática, com a finalidade de auxiliar o médico, sobretudo o clínico geral, o dermatologista e o otorrinolaringologista, no diagnóstico de tais patologias.

Pseudotumor resulting from atypical mycobacterial infection: a "histoid" variety of Mycobacterium avium-intracellulare complex infection.

A 54-year-old immunosuppressed cardiac transplant recipient with a six-month history of progressive swelling of the hand, with nodules and linear lymph node chain enlargement, diagnosed as a sporotrichoid Mycobacterium avium-intracellulare pseudotumor is described. The microscopic features closely resembled the previously described histoid variety of lepromatous leprosy. Routine hematoxylin and eosin staining suggested a spindle cell neoplasm rather than an infectious or inflammatory process. An infectious etiology was pursued on the basis of the clinical setting.