Peer-reviewed veterinary case report
Pseudohyperparathyroidism in a mare associated with squamous cell carcinoma of the vulva.
- Journal:
- The Cornell veterinarian
- Year:
- 1990
- Authors:
- Karcher, L F et al.
- Affiliation:
- Department of Clinical Sciences · United States
- Species:
- horse
Plain-English summary
An 18-year-old Appaloosa mare was seen by a veterinarian because she had a fast-growing tumor called squamous cell carcinoma on her vulva, was not eating and had lost a lot of weight. Over three months, the tumor spread to other areas, including the perineum and the udder. A thorough examination after her passing showed that the cancer had also spread to several lymph nodes, but her kidneys appeared normal. Tests indicated that her high calcium levels were likely due to the cancer rather than other causes, suggesting that the tumor might be producing a substance that raises calcium levels in the blood. Unfortunately, despite the findings, the exact cause of the high calcium was not identified, and the mare's condition was serious due to the cancer's spread.
Abstract
An 18-year-old Appaloosa mare was examined because of squamous cell carcinoma of the vulva, anorexia with pronounced weight loss, and hypercalcemia. The tumor had developed rapidly over a period of 3 months and externally extended ventrally involving the perineum and the dorsal aspect of the udder. Necropsy examination demonstrated a large primary squamous cell carcinoma of the vulva, perineum, and mammary gland with metastases to the supramammary, sublumbar, deep inguinal, and mediastinal lymph nodes. No gross renal lesions were observed and, histologically, there was only mild vacuolation of renal tubular epithelium. Based on the normal concentration of serum parathyroid hormone, the absence of evidence of hypervitaminosis D, and normal renal function, a diagnosis was made of hypercalcemia of malignancy or pseudohyperparathyroidism. The mechanism responsible for hypercalcemia was not determined, but the histologic type of the neoplasm and the clinical course suggested possible production of a humoral hypercalcemic factor by the neoplasm, similar to that demonstrated in certain types of human squamous cell carcinoma.
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Search related cases →Original publication: https://pubmed.ncbi.nlm.nih.gov/2318041/