Non-metastatic squamous cell carcinoma in two Hermann’s tortoises (Testudo hermanni)

Squamous cell carcinomas (SCC) are malignant tumors of the epidermal cells with varying degrees of keratinocyte differentiation. They are common tumors in mammalian and avian species but there are, however, only two description of SCC in tortoises. In this case report we describe two cases of non-metastatic squamous cell carcinomas of the carapax and the plastron in Hermann’s tortoises with evidence of humoral hypercalcemia of malignancy (HHM) in one case. HHM is thought to be associated with SCC in mammals due to de novo secretion of parathyroid hormone-related protein (PTHrP) by the tumor cells or tumor induced osteolysis but has not been described in reptiles so far.