Feline paraneoplastic alopecia associated with metastasising intestinal carcinoma

Abstract

Case summary: A 10-year-old male neutered British Shorthair cat was presented with a 6 month history of lethargy, weight loss and alopecia. Clinical examination revealed widespread alopecia of the ventral abdomen and hindlimbs. The skin in these areas was smooth and shiny and hairs could be easily epilated. Spontaneous pruritus was observed. Cytological examination of superficial impression smears showed a severe Malassezia species dermatitis and pyoderma. Ectoparasites could not be detected and no sign of dermatophytosis was visible in trichograms and Wood's lamp analysis. Abdominal ultrasound found a focally thickened wall of the large intestine and multiple nodules in the liver. Fine-needle aspirates from lymph nodes, liver and altered colonic wall were consistent with an undifferentiated malignant neoplasia. The cat was euthanased at the owners' request, owing to potential neoplasia with metastatic spread. At necropsy a metastasising carcinoma of the colonic wall was found, as well as a paraneoplastic alopecia.

Relevance and novel information: Feline paraneoplastic alopecia has been reported in association with pancreatic carcinoma, bile duct carcinoma and hepatocellular carcinoma, as well as with neuroendocrine pancreatic carcinoma and hepatosplenic plasma cell tumour. This is the first reported case of feline paraneoplastic alopecia associated with a colon carcinoma.

Figure 1

Widespread alopecia on the ventral abdomen and the hindlimbs. The skin is diffusely erythematous and smooth with small crusts

Figure 2

Cytology of abdominal lesions. Atypical neoplastic cells were detectable within fine-needle aspiration of lymph node, intestine and liver. Cells are increased in size with a high amount of basophilic cytoplasm, round-to-oval nuclei and prominent nucleoli. Numerous mitotic figures (arrowhead) were obvious. Pappenheim stain (× 100)

Figure 3

(a) Ulcerated exophytic neoplasia of the colonic wall. (b) Abundant transplantational metastases within the omentum. (c) Liver metastases (arrowheads)

Figure 4

(a) Histopathology of the skin: moderate epidermal hyperplasia, atrophic, mostly telogen and kenogen hair follicles. (b) Area with parakeratosis, crusts and superficial dermatitis. Haematoxylin and eosin (× 20)

Figure 5

Colon: in the upper left corner ulceration of the mucosa and transmural infiltration with neoplastic cells and desmoplastic response. Haematoxylin and eosin (× 10). Inset: nests of neoplastic cells within lymph vessles. Haematoxylin and eosin (× 40)