Clinical, Diagnostic, and Pathological Features of 2 Cases of Metastatic Iridophoroma in a Veiled Chameleon (Chamaeleo Calyptratus) and a Red-Barred Dragon (Ctenophorus Vadnappa)

Chromatophoromas in Reptiles

“…Of the different reptilian orders, they are most frequently described in squamata with few reports in testudines (chelonia) and no reports in crocodilia or rhynchocephalia [ 9 , 11 , 12 , 13 , 14 , 19 , 20 , 21 ] Affected animals are almost always adults and no sex predilection is apparent [ 9 , 11 , 12 , 13 , 14 ]. Most reports are cutaneous chromatophoromas that develop as single or multiple masses at various sites, including the head, trunk, limbs (when applicable), and tail [ 9 , 12 , 13 , 22 , 23 ]. Chromatophoromas most often present as raised, pigmented masses, but more subtle alterations in scale pigmentation are less commonly described [ 9 , 12 , 13 , 14 ] ( Figure 1 a–e).…”

“…Cytologic examination, including fine needle aspirates and impression smears, can be a minimally invasive method to diagnose chromatophoromas. In a few reptile cases this diagnostic technique successfully identified the mass as a chromatophoroma [ 19 , 20 , 21 , 23 , 27 , 36 , 37 ]. In all these cases, the diagnosis was subsequently confirmed by histologic examination.…”

“…In all these cases, the diagnosis was subsequently confirmed by histologic examination. Cytologic findings using Romanowsky-type stains included discrete to aggregated stellate, spindloid, or round cells that contained scant to copious amounts of fine, intracytoplasmic dark blue to black granular material [ 19 , 20 , 21 , 23 , 27 , 36 , 37 ]. Neoplastic melanophores contained green, black, or brown melanin granules [ 19 , 20 , 21 , 27 , 37 ].…”

“…Neoplastic melanophores contained green, black, or brown melanin granules [ 19 , 20 , 21 , 27 , 37 ]. Neoplastic iridophores contained olive green or light brown refractile granules [ 23 , 36 ]. Microscopic examination with polarized light can be utilized to identify iridophoromas, as the granules are birefringent [ 23 , 36 ].…”

“…Neoplastic iridophores contained olive green or light brown refractile granules [ 23 , 36 ]. Microscopic examination with polarized light can be utilized to identify iridophoromas, as the granules are birefringent [ 23 , 36 ]. There can be abundant extracellular pigment granules [ 20 , 23 , 27 ] ( Figure 3 a,b).…”