The giant hornbill (Buceros bicornis) has been reported with invasive squamous cell carcinoma (SCC) of the casque, predominantly in males (n=9, 6.3). To date, no explanation has been found for the predisposition to this neoplasia in this location for the captive species. Of interest and possible source of explanation, the casque coloration (orange and yellow, caretonoids) for this and other other Asian hornbills, is transferred through preening the pigments originating in the uropygial gland oils.

Diet composition has the ability to affect the character and composition of these oils, specifically the caretonoids within the secreta. In turn, this could alter the casque keratin pigmentation. It is documented in mammals that skin pigmentation can affect the location and appearance of SCC. This occurs notably with areas of lesser pigmentation being more susceptible to neoplastic transformation in response to ultraviolet radiation.

It is hypothesized that changes in casque pigmentation is occurring in the giant hornbill that leaves some individuals more prone to SCC development.

To assess this, uropygial secreta and tissues are requested from the following species:

giant hornbill (Buceros bicornis)
rhinoceros hornbill (Biceros hydrocorax)

These will be utilized to evaluate baseline secreta composition, specifically for carotenoids, and casque and uropygial gland histology, and composition of the casque. Comparison will be made between normal and abnormal captive specimens of both genders. Ultimately, similar collection of secreta from free-ranging specimens would serve as "control" for the captive animals.

At annual or opportunistic examinations:

* Express the uropygial gland by gentle digital manipulation through the papillae

- trap the secreta onto clean filter paper

- estimate the secreta volume (record in pencil on filter paper, include ID of bird)

- allow sample to air dry then store in clean ziplock bag at room temperature

- submit filter paper to Coraciiformes TAG (hornbills) Veterinary Advisor

At post-mortem examinations:

* Complete excision of the intact uropygial gland

- full tissue thickness splitting of this tissue horizontally through both lobes

- express one half of the gland from cut edge onto clean filter paper

- allow secreta to air dry then store in clean ziplock bag at room temperature

- store the expressed gland portion in formalin (1:10 tissue: formalin)

- store the unexpressed gland portion frozen (prefer ultralow)

- submit filter paper and both portions of gland to Coraciiformes TAG (hornbills) Veterinary Advisor

* Punch biopsy (3) of casque (5-10mm diameter)

- collect sample from left, right, and dorsal casque

- store the individually identified biopsies frozen (prefer ultralow)

- submit to Coraciiformes TAG (hornbills) Veterinary Advisor

Veterinary Advisor, Coraciiformes TAG (hornbills):

Kathryn C. Gamble DVM, MS, DACZM
Director of Veterinary Services
2001 North Clark St.
Chicago, IL L60614
Ph: 312.742.7722; Fx: 312.742.7823
kgamble@lpzoo.org