Sentinel Lymph Node Mapping with Indirect Lymphangiography for Canine Mast Cell Tumour

Abstract

Mast cell tumour (MCT) is a common cutaneous and subcutaneous neoplasia in dogs. It can metastasise to lymph nodes (LNs), and this adversely affects the prognosis and treatment. The study aims to evaluate the SLN mapping of MCTs with radiographic indirect lymphography. Dogs that underwent clinical staging were prospectively enrolled. Lipiodol was injected around the MCT or the surgical scar. After 24 h, LNs that picked up contrast were radiographically assessed. Twenty-six dogs with 29 MCTs were included. MCTs were confirmed histologically, while SLNs were evaluated either by cytology and/or histology. SLNs were detectable in 23 dogs with 26 MCTs. Lymphatic vessels were visible in 19 MCTs. In nine MCTs, at least two SLNs picked up contrast. In particular, seven MCTs involved two SLNs, and two MCTs involved three different SLNs. In nine MCTs, at least a SLN was metastatic. This study indicates that the lymph drainage pattern of the MCTs may be different for each MCT, and more than one SLN can be involved. Indirect lymphangiography with Lipiodol allowed the detection of the SLN in 90% of MCTs. This provided clinically relevant information to remove the LN and stage the patient.

Patterns of nodal metastases, biological behaviour and prognosis of canine mast cell tumours of the pinna: A multi‐institutional retrospective study

“…In agreement with previous studies, 14–16 the results of the current work suggest that the superficial cervical LN is most often the SLN in cMCTs of the pinna, as in approximately 95% of cases the superficial cervical LN was at least one of, if not the only SLN.…”

“…Additionally, the superficial cervical LN was never investigated, possibly missing metastatic foci. Our results confirm in a larger population the findings of De Bonis and colleagues, where one out of two dogs with cMCTs of the pinna had SLN metastasis (superficial cervical LN; HN3) 15 …”

“…LN metastases at the time of diagnosis were not identified in any of the dogs, but LN assessment was not performed in most (92.8%) cases 12 . Overall, data on pinnal cMCT remain scarce and outdated when considering the knowledge acquired over the past years on histologic tumour and LN gradings, and the value of LN staging 10,12,14–17 …”

“…Based on anatomic studies, most of the lymph vessels of the pinna drain to the superficial cervical LN. A small number drain to the lateral retropharyngeal and medial retropharyngeal LNs, as well as to the parotid LN 12–22 . The sentinel lymph node (SLN) is defined as the first LN receiving drainage from a primary tumour and is expected to be the first site of metastasis.…”

The Role of Sentinel Node Mapping and Lymphadenectomies in Veterinary Surgical Oncology

“…Most recently, De Bonis et al demonstrated that indirect lymphography using lipidiol and serial radiographs resulted in the detection of at least one SLN in 90% of cases [81]. Their study also described a high discrepancy between RLNs and SLNs, with only 27% full agreement, and interestingly, they also described a considerably lower rate of 50% than other studies utilizing more efficient SLN methods [94].…”