Dog Lump Under Skin

" Dog lump under skin issues are either a cellular mass, a tumor of the connective tissues or are deeply connected to the soft tissues of the dermal or skin layers. These may be benign fibroblastic tumors, nerve sheath tumors, vascular tumors or smooth tissues tumors. Lumps under a dogs skin are characterized by deeper roots in the soft tissues, a nodular appearance, are usually benign in nature (not cancerous, slow growing) and usually not painful. Some dog breeds like shepherds and poodles may be predisposed to these lumps. Lumps under the skin are usually attached to a root, which is embedded in the soft tissues. Due to a fair supply of blood and oxygen, these nodules can grow larger with the passage of time, also some lumps under a dog’s skin can mutate into a malignant form of tumor (cancerous, fast growing). It is therefore recommended that lumps be treated either surgically or preferably with drugs. "

Types of Dog Lump Under Skin:

On palpation, dog lumps can be felt under the skin, and may or may not painful. These may displace (move) under pressure and are usually attached to a base, with the root of the lump located deep in the soft tissues of the muscles

Types of dog skin lumps:

• Benign Fibroblastic Tumors; Collagenous Nevi and fibromas are a common benign form of fibroblastic tumors in dogs. Collagenous Nevi, is made up of dermal collagen, which is a protein of connective tissues collected in a large amount under skin. Fibromas on other hand are accumulation of fibroblast tissues in the skin, these cells in mass appears as nodules beneath skin. Hair loss is also associated with this form and hairless raised mass originates in deep skin fats. 
• Nerve Sheath Tumors: This form of lump is common in those dogs which undergoes cosmetic surgery like tail docking, ear trimming etc. These are non neoplastic or non cancerous in nature and are caused by an unsystemic proliferation of parenchyma cells which are a response to amputation or trauma. Young dogs are more susceptible and reoccurrence is common in those dogs which have a repeated trauma at the site of surgery. Such lumps are painful and swelling is common. 
• Vascular Tumors: Vascular tumors are caused by the blood vessels beneath the skin. In dogs, hemangiomas are the most common form of vascular tumor. Canine lumps under the skin appear as a raised surface, also termed a “Blood Blister”. Extremities of organs and the trunk are the most common sites for such lumps. Many dog breeds such as Gordon setters, boxers & terriers are considered more susceptible. 
• Smooth Tissue Tumors: Leiomyomas & Leiomyosarcomas are two forms of tunors that cause lumps under canine skin. Usually these are malignant. They are characterized by a solid dermal mass, which is spongy on palpation. Leiomyomas are small and are limited to the skin. Leiomyosarcomas are larger in size and distributed on the skin and in fat under the skin.
  

Diagnosis of Dog Lump Under Skin:

The appearance of the lumps and clinical examination is usually helpful in identifying the type of lump. Tumors under skin can be diagnosed by biopsy and with laboratory examination. Dog lumps under skin should be differentiated with those that occur over the epidermal layers (outer layers) of the skin by making note of any stalk or root which is embedded in the soft tissues of the skin or in fat under the skin.

Treatment of Dog Lump Under Skin:

Most dog lumps which occur under skin usually do not require treatment since they do not cause any systemic harm to dogs. Resection is only effective and preferred option for treating these lumps. Other surgical procedures effective are cryo surgery, electro surgery & complete resection. Resection should be made complete including roots & deep penetration. For complete eradication chemotherapeutic agents, adriamycin combined with cyclophoshamide, dacarbazine or methotrexate can be used.

Treatment plans should be determined by a veterinarian or a veterinary oncologist.

References:

References:

The Merck/Merial Manual for Pet Health (Home Edition)