Primary adrenal lymphoma causing hypoaldosteronism in a cat

Abstract

Case summaryA 10-year-old, 5.1 kg (11.2 lb), male castrated cat was presented with signs of lethargy and decreased appetite at home after being previously healthy. Serum biochemical analysis identified normokalemia (5.1 mmol/l; reference interval [RI] 3.4–5.6 mmol/l) and severe hyponatremia (123 mmol/l; RI 145–158 mmol/l), with an Na/K ratio of 24 (RI 32–41). Baseline serum cortisol was low to normal, but serum aldosterone was markedly decreased with a pre-adrenocorticotropic hormone stimulation concentration of 13 pmol/l (RI 194–388 pmol/l) and post-adrenocorticotropic hormone stimulation concentration of 21 pmol/l (RI 277–721 pmol/l). Hematologic and biochemical analyses were otherwise unremarkable. Abdominal ultrasound revealed bilaterally enlarged adrenal glands with no other abnormalities noted; thoracic radiographs also did not identify any signs of metastasis. Fine-needle aspiration was strongly suggestive of lymphoma of the adrenal glands, and PCR for antigen receptor rearrangement was positive for B-cell clonal expansion; based on these findings, a diagnosis of primary adrenal B-cell lymphoma was made. Stable disease was achieved for a short period of time following vincristine, cyclophosphamide, prednisolone and fludrocortisone therapy, followed by progressive adrenal enlargement and electrolyte derangements that responded to neither doxorubicin nor adjustments in fludrocortisone dosage. Ultrasonographic metastasis was not identified at any time, and other organ derangements were not noted on hematologic or biochemical analyses. The cat was euthanized 55 days after initial presentation.Relevance and novel informationThis is the first report of primary adrenal lymphoma in a cat, with presenting signs compatible with hypoaldosteronism. Lymphoma should be a differential for cats presenting with adrenal enlargement or clinical signs and biochemical changes consistent with hypoaldosteronism or hypoadrenocorticism.

Hypoadrenocorticism in an aged cat

“…Hypoadrenocorticism is an extremely rare endocrinopathy in cats. [1][2][3][4][5][6][7][8][9][10][11][12][13][14][15][16][17][18][19] From the case reports that have been published, cats seem to present with similar clinical signs and physical examination findings as dogs. Additionally the biochemical, electrolyte and haematological derangements are also comparable.…”

“…Additionally the biochemical, electrolyte and haematological derangements are also comparable. Typical, atypical, iatrogenic, traumatic and neoplastic causes of primary hypoadrenocorticism have been reported in cats, [1][2][3][4][5][6][7][8][9][10][11][12][13][14][15][16][17] and recently cases of secondary hypoadrenocorticism have been documented. 8 11 The ACTH stimulation test is the gold standard for diagnosis of hypoadrenocorticism in cats, as it is in dogs, although the protocol is different.…”

“…Relatively few cases have been documented in the literature or in book chapters since the first case was reported in 1983. [1][2][3][4][5][6][7][8][9][10][11][12][13][14][15][16][17][18][19] Hypoadrenocorticism can be categorised into either primary or secondary disease. Primary hypoadrenocorticism results from destruction of the adrenal cortex and consequent inadequate production of glucocorticoids and mineralocorticoids.…”

“…14 15 In one case report of a cat with hypoadrenocorticism, histopathology of the adrenal gland on postmortem examination showed lymphocytic infiltration of the cortex, which supports an immune-mediated cause in that case. 1 Additionally infiltration and destruction of the adrenal cortex from primary 4 and metastatic 3 lymphoma is reported as a cause of hypoadrenocorticism in cats. Two cases of traumatically induced hypoadrenocorticism have also been documented.…”

Hypoadrenocorticism in two cats successfully treated with desoxycorticosterone pivalate

“…In case 2, the ultrasonographic and laparotomic findings of enlarged lymph nodes and thickened intestinal walls were initially suggestive of an intestinal lymphoma. Primary adrenal lymphoma11 or metastatic adrenal lymphoma12 resulting in hypoadrenocorticism has been reported in cats. While an adrenal lymphoma was a possibility in case 2, this is unlikely since (A) ultrasound showed none of the adrenals to be enlarged, (B) histopathology could not diagnose lymphoma in any of the biopsies and (C) PARR was polyclonal.…”