Mesenchymal Tumors of Some Estuarine Fishes of the Northern Gulf of Mexico. I. Subcutaneous Tumors, Probably Fibrosarcomas, in the Striped Mullet, Mugil Cephalus

We report fibrous tumors occurring in the subcutaneous tissues of five striped mullet taken from Mississippi Sound. These nonpedunculated tumors were associated with ulceration of the overlying integument. Affected mullet exhibited 1 to 10 tumors on most surface-areas of the body, excluding the fins. Consisting primarily of fibroblast-derivatives, these well- to poorly-differentiated tumors are considered pathologically malignant, i.e., fibrosarcomas. Invasion into and nearly through the fascia overlying the muscle, focal necrosis, and cellular atypia support this interpretation. Metastases were not observed. Thus, these tumors could represent benign fibromatoses or fibromas. We suggest a possible relationship between these neoplasms in the mullet and increasing pollution in Mississippi Sound.