CANINE  LYMPHOMA

              The lymphoma (malignant lymphoma or lymphosarcoma ) are a diverse group of neoplasms which originates from lymphoreticular cells. 

             They usually arise in lymphoid tissues like lymph nodes, spleen and bone marrow. However they may arise in almost any tissue in the body. Lymphoma one of the most common neoplasms in dogs and is one of major (5th cause ) 'cause of canine mortality. Non-Hodgkin's lymohoma accounts 5% of all new cancer cases in canines.

                Dog breeds which are susceptible to lymphoma are Boxers, Retrievers, Bull Mastiffs, Basset Hounds, Saint Bernards, Scottish terriers, Airedales, Bulldogs. Breeds which are less susceptible are Dash-hounds and Pomeranians.

                Etiology -is unknown and multifactorial. Broadly factors are 1). Genetic and molecular
2). Infectious 3). Environmental ( herbicides and  strong magnetic fields) 4). Immunosuppression 

                Lymphomas are classified by various systems out of which (NHC), HCI updated  Kiel system and revised EAL systems are important. But WHO' s clinical staging system for lymphosarcoma in domestic animals is the most followed system. 

                Hypercalcemia and anemia, with CNS depresion are considered to be pathognomonic symptoms. Complete Blood count, biochemistry, urine analysis, Histological and cytological evaluation of lymph nodes  with FNAC technique, Molecular diagnostic techniques (PCR), and clonality assay are methods used for clinical staging  of diasease .

               Lymphoma are treated with radicle surgery followed by palliative radiation, multidrug or single drug chemo therapy for which lymphoma protocol is available. 

               Although canine lymphoma has rarely curable, prognosis mainly varies and depends on number of factors such as location of disease, extent of disease, presence or absence of clinical signs, the histologic grade, the immunophynotype  (T cell or B cell ), exposure to previous chemotherapy or corticosteroids and subsequent development of MDR, altered cell death processes ( apoptosis), the proliferation rate of the tumor, the presence of paraneoplasitc conditions and possible gender.      

LARYNGEAL TUMORS

Laryngeal Tumors are rare in nature and include Rhabdomyoma (oncocytoma ), osteosarcoma, extramedullary plasma cytoma, chondrosarcoma, undifferentiated carcinoma fibrosarcoma, mastcell tumors, adenocarcinoma and sqamous cell carcinoma.

         Patients with laryngeal carcinoma usually have a progressive change in voice or bark,exercise intolerance or dysphagia.

        Diagnosis of such tumors is very easy because of easy direct biopsy, FNAC and digital radiography.

        Benign laryngeal tumor of cysts can be removed surgically with better results. But in malignancy laryngectomy with permanent tracheostomy which is best options for humans can not be undertaken in canines. 

         Radioresponsive tumors can be irradiated with palliative rediotherapy with 35 to 45 Gy. radiation potential. Benign tumors have good prognosis. Unfortunately very limited information is available for malignant tumors and their treatment because very few have been treated and reported. 

        Doxirubicin is a drug of choice for chemotherapy and palliative  radiation with 32 to 45 Gy. can pull patient's life upto 1 year maximum.

        

Peripheral Nerve Sheath Tumors.

(PNST)

PNST are malignant tumors of nerve sheath origin and have been referred to as neurofibrosarcoma, malignant schwannoma and haimangiopericytoma. They occur any where in body. PNST are divided mainly in three groups 

1. Peripheral group -  PNST involves nerves away from brain or spinal cord.

2. Root group - Involves nerves immediately adjescent to brain or spinal cord

3. Plexus group - involves brachial or lumbosacral plexsus

       True peripheral forms of PNST are easily treatable.

PNST are poorly defined tumors and appear like fibrosarcomas. They are adherent to deeper tissues and infiltrate underlying fascia,muscle and skin.

        All PNST's are malignant but have moderate metastetic rate. Recurrence after conservative surgery is very common. modified staging and grading system for these PNST is available.

         The best chemotherapeutic agent is doxorubicin and palliative radiation at the rate of 30 Gy usually undertaken.Survival is 12 to 24 months maximum, reported after diagnosis.