Overview

• Lymphomatoid granulomatosis is a rare lymphoproliferative disorder predominantly involving the lungs.
• Rare pulmonary disease of dogs and cats characterized by angiocentric and angiodestructive proliferation and infiltration by atypical lymphoid cells.

Signalment

• Dog and cat
• Median age-5.75 years (range, 1.5–14 years) in dogs
• No breed predilection but more common in large breeds and pure breeds
• No gender predisposition

Signs

• Progressive respiratory signs including cough and dyspnea
• Serous nasal discharge
• Exercise intolerance
• Weight loss
• Anorexia
• Fever in 50% of patients
• Duration- days to weeks

Causes & Risk Factors

Unknown

Differential Diagnosis

• Mycotic, bacterial, or aspiration pneumonia
• Primary or metastatic pulmonary neoplasia
• Atypical pulmonary lymphoma

CBC/Biochemistry/Urinalysis

• No consistent abnormalities
• Neutrophilic leukocytosis, eosinophilia, and basophilia may be common

Other Laboratory Tests

Some dogs have concurrent heartworm disease and/or test positive for heartworms.

Imaging

• Radiography-reveals lobar pulmonary consolidation (e.g., mass lesions), hilar lymphadenomegaly, and pleural effusion.
• Lesions-unilateral or bilateral.

Diagnostic Procedures

• Biopsy-for definitive diagnosis (adequate tissue sample size required for accurate diagnosis).
• Immunohistochemistry is required on the biopsied tissue (CD3, CD20, CD79).

Pathologic Findings

• Gross-multiple pulmonary nodules with a predilection for the caudal lung lobes with metastasis or involvement of hilar lymph nodes.
• Histologic-characterized by sheets of atypical lymphoid and plasmacytoid cells admixed with fewer eosinophils and small lymphocytes in the pulmonary blood vessels. The lymphocytes can be of B-cell and T-cell lineage, with Reed-Sternberg-like cells reported.
• Cytologic-may appear as sterile eosinophilic and neutrophilic inflammation with reactive macrophages.
• Systemic spread is possible-to liver, heart, kidneys, spleen, pancreas, adrenal gland, and other organs.

Drug(s)

Combination protocol-CHOP or other combination protocol suitable for lymphoma. No standard treatment protocol has been systemically evaluated.

Contraindications/Possible Interactions

• Myelosuppression-caused by cytotoxic drugs
• Hemorrhagic cystitis-caused by cyclophosphamide

Patient Monitoring

Same as for lymphoma treated by chemotherapy

Possible Complications

• Dyspnea as disease progresses
• Depression
• Anorexia
• Myelosuppression caused by chemotherapy

Expected Course and Prognosis

Median survival in dogs with systemic chemotherapy has been reported to be approximately 12 months; however, range for survival may be broad based upon initial response to therapy. The reported survival is compounded by the difficulty of accurately diagnosing the disease.

Associated Conditions

No known definitive associations

Synonyms

• Eosinophilic pulmonary granulomatosis
• Granulomatosis
• Lymphoid granulomatosis
• Lymphoproliferative angiitis

Abbreviation

CHOP = cyclophosphamide, hydroxydaunorubicin (doxorubicin), vincristine (Oncovin), and prednisone