Vasoproliferative process resembling pulmonary capillary hemangiomatosis in a cat

Abstract

BackgroundPulmonary capillary hemangiomatosis is a rare, vascular obstructive disorder that uniformly causes pulmonary arterial hypertension. Clinically, pulmonary capillary hemangiomatosis is indistinguishable from primary pulmonary arterial hypertension and histology is required for definitive diagnosis. The distinctive histologic feature of pulmonary capillary hemangiomatosis is non-malignant extensive proliferation of capillaries in the alveolar septae. Vasodilator treatment of humans with primary arterial hypertension due to pulmonary capillary hemangiomatosis can result in fatal acute pulmonary edema. Computed tomography is thus critical to discern pulmonary capillary hemangiomatosis from other causes of pulmonary arterial hypertension prior to vasodilator therapy. This is the first report of a vasoproliferative process resembling pulmonary capillary hemangiomatosis in the feline species.Case presentationA 15-year-old, male castrated, domestic shorthair cat presented for persistent labored breathing presumptively due to congestive heart failure despite treatment with diuretics for 7 days. Echocardiography showed evidence of hypertrophic cardiomyopathy with severe pulmonary hypertension; however, a normal sized left atrium was not consistent with congestive heart failure. Thoracic computed tomography was performed and showed evidence of diffuse ill-defined nodular ground glass opacities, enlarged pulmonary arteries, and filling defects consistent with pulmonary thromboembolism. The cat acutely decompensated after a single dose of sildenafil and was euthanized. Histopathology of the lungs showed severe multifocal alveolar capillary proliferation with respiratory bronchiolar infiltration, marked type II pneumocyte hyperplasia and multifocal pulmonary arterial thrombosis.ConclusionThis is the first description in a cat of a vasoproliferative disorder resembling pulmonary capillary hemangiomatosis complicated by multifocal pulmonary arterial thrombosis. Inspiratory and expiratory ventilator-driven breath holds with angiography revealed lesions predominantly characterized by ground glass opacification and vascular filling defects with absence of air trapping. The results from this report suggest that, as in humans, the cat can develop a pulmonary capillary hemangiomatosis-like disease in which vasodilator therapy to address pulmonary hypertension may lead to fatal pulmonary edema.

Clinical features of canine pulmonary veno‐occlusive disease and pulmonary capillary hemangiomatosis

“…Major differentials for canine PH in this scenario would include PTE (because of a variety of causes, including but not limited to hypercoagulable states and neoplastic or parasitic emboli), interstitial lung disease, non‐cardiogenic pulmonary edema, and causes of PAH (idiopathic PAH, PVOD, and PCH) . The authors are unaware of any studies to date evaluating the CT characteristics of dogs with spontaneous idiopathic PAH, PVOD, or PCH, and only a single case report describes CT features in a cat with a vasoproliferative disorder resembling PCH …”

“…Although treatment with pulmonary vasodilators can improve the survival times of humans with idiopathic PAH and dogs with other forms of PH, fatal or life‐threatening pulmonary edema may result in cases of PVOD or PCH when there is relative vasodilatation of the precapillary resistance vessels with fixed resistance at the level of the capillaries or venules . Oral administration of sildenafil to a cat with PCH‐like disease was speculated to cause acute massive pulmonary edema that ultimately contributed to death . Adverse response to vasodilators is not always immediate, with one study of 24 human cases of PVOD showing 9 days as the median time from the start of treatment to development of pulmonary edema (range, 1‐240 days) .…”

Left Pulmonary Artery Coarctation Associated with Pneumonia and Pulmonary Hypertension in a Cat

“…2021, 8, x FOR PEER REVIEW 2 of 8 PH) from post-capillary PH, in which both PAP and PAWP are increased (i.e., type 2 and 6 PH) [6]. In cats, PH is uncommonly reported and, with the exception of a recent case series of 22 cats with post-capillary PH secondary to left-sided congestive heart failure [7], the majority of reports are single case descriptions of PH associated with congenital cardiovascular disease [8][9][10], pulmonary fibrosis and chronic upper airway obstruction [11,12], pulmonary thromboembolism [13], parasitic diseases [14,15], and pulmonary capillary hemangiomatosis [16].…”

“…Sci. 2021, 8, 325 2 of 8 series of 22 cats with post-capillary PH secondary to left-sided congestive heart failure [7], the majority of reports are single case descriptions of PH associated with congenital cardiovascular disease [8][9][10], pulmonary fibrosis and chronic upper airway obstruction [11,12], pulmonary thromboembolism [13], parasitic diseases [14,15], and pulmonary capillary hemangiomatosis [16].…”

Recent advances in our understanding of the mechanisms of lung alveolarization and bronchopulmonary dysplasia

“…Nomenclature and terminology continue to be problematic in the field of lung alveolarization and BPD. A recent plea was made for the proper pluralization of "septum" as "septa" (402), and yet, the continued use of the incorrect "septae" persists in the "lung literature," (56,226,234,347,350,422,424,551,607). The pluralization of "alveolus" has also seen the recent introduction of a new misnomer: "alveolae" (594) instead of the correct form, "alveoli.…”