Canine Cutaneous and Subcutaneous Soft Tissue Sarcoma: An Evidence-Based Review of Case Management

Abstract

Canine cutaneous and subcutaneous soft tissue sarcomas (STS) account for 20.3% of malignant neoplasms of the skin. This article makes recommendations for the diagnosis, treatment, and follow-up in dogs with STS, using evidence-based medicine concepts. Although our review of the literature on the management of canine STS found many of the studies to be less than rigorous, board-certified specialists in internal medicine, surgery, pathology, oncology, and radiation oncology were able to make several recommendations based on the literature review: cytology and biopsy are important for presurgical planning; wide (>3 cm margins) surgical excision decreases the likelihood of tumor recurrence; the use of a histologic grading scale is useful in predicting biologic behavior; and, in select cases, chemotherapy and radiation therapy may be beneficial adjunct treatments to surgical excision. More research is necessary to determine minimum size of surgical margins, the impact of radiation therapy on incompletely resected tumors, the ideal chemotherapy protocol for high grade STS, and the optimal methods of monitoring dogs for tumor recurrence and metastasis.

Malignant Soft Tissue Sarcoma at the Site of Corticosteroid Injection in a Dog

“…Fibrosarcomas can be associated with injection site sarcomas (ISS) in cats and occasionally dogs [1][2][3]. There are some documented cases of dogs having ISS, which show similar histopathological characteristics to those seen in cats, such as, subcutaneous location, areas of necrosis, inflammatory response, and neoplastic mesenchymal cells [3].…”

“…However, histiocytic sarcoma, hemangiosarcoma, osteosarcoma, malignant melanoma and oral sarcoma are excluded. Since this particular soft tissue mass in our case report expressed abundant intercellular collagenous/myxoid matrix and did not exhibit a cellular pattern or cytomorphology typically seen in hemangiopericytoma, peripheral nerve sheath tumor or other sarcomas, it was further classified as a fibromyxosarcoma [1,2]. Soft tissue sarcomas are graded from 1-3 based on level of differentiation, mitotic index and necrosis [1,2].…”

Significant advances in veterinary oncology – 60 years on

“…Although soft tissue sarcomas may arise at many sites, the majority in dogs and cats affect the skin, subcutis or deeper connective tissues, and most of the following discussion is focused on tumours at these more common sites. There are many articles that document histological features and classification schemes for soft tissue sarcomas and this has changed and improved over the years as a result of advances in histological and immunohistochemistry techniques (Dennis et al 2011, Hohenhaus et al, 2016. For example, the term "malignant fibrous histiocytoma" was historically used to describe a group of pleomorphic sarcomas of different origins containing mixtures of round, spindle and multinucleated giant cells (Kerlin & Hendrick 1996) that are now largely classified as part of the histiocytic sarcoma complex, whose myeloid dendritic origin is demonstrated by expression of CD1, CD11c, MHC class II and ICAM-1, and more recently CD18 and Iba-1 (Affolter & Moore 2002, Pierezan et al 2014.…”

Emerging therapeutic approaches for canine sarcomas: Pushing the boundaries beyond the conventional

“…Treatment of canine soft tissue sarcomas is largely similar to treatment in humans, with surgery, radiation therapy (RT) and chemotherapy providing the underlying platform for both species . Surgical resection with complete histologic margins is the treatment of choice for soft tissue tumours and yields long‐term control in many paediatric and canine patients; incomplete margin status is associated with a high likelihood of tumour recurrence . In dogs, wide excision is recommended and local tumour recurrence is more likely following conservative excision, with high‐grade or undifferentiated tumours more likely to recur .…”