Malignant priapism: when is a computed tomography scan indicated?
Johnson, M1; Skrodzka, M1; Johnson, T1; Chiraco, G1; Christopher, A1; Ralph, D1
1: University College London Hospital, United Kingdom
Introduction: Ischaemic priapism (IP) is characterised by a persistent, painful penile erection lasting for >4 hours. Many causes of IP have been identified including haematological dyscrasias (particularly, sickle cell disease), drugs and rarely malignancy. There are also a large proportion of men, in which no aetiology is identified. IP secondary to malignancy occur via 2 distinct aetio-pathogeneses: (1) Penile metastases; (2) Pro-thrombotic factors secondary to malignancy.
Methods: We retrospectively reviewed every case of ischaemic priapism within our institution over a 10 year period (2007-2017) and identified all cases of malignant priapism (MP). Twenty consecutive men with idiopathic IP were identified and used as a control. Significance was determined using a Mann and Witney U-test.
Results: We identified 861 episodes of priapism that occurred in 412 men. Within our population the prevalence of malignant priapism was 2.4% (n = 10). 40% (n = 4) of these men had a known diagnosis of cancer prior to their episode of priapism. MP secondary to penile metastases occurred in 7 of the 10 men (Bladder x 3, Prostate, Lung, Urethral and Chondrosarcoma of the pelvis). MP secondary to haematological malignancy occurred in the remaining 3 (Chronic Lymphocytic Leukaemia, Chronic Myeloid Leukaemia and Myelodysplasia). An abnormally low haemoglobin value (reference range 130-180 g/dl) was found in 80% of the men with MP compared to 20% in the control. The mean haemoglobin value in men with MP was 110.9 g/dl (SD = 19.9) compared to the control of 142.6 g/dl (SD = 15.5). This difference was considered highly significant p= 0.00124. Men with MP also appears to have a very poor prognosis with a 12 month mortality of 40% (n = 4) and an 18 month mortality of 70% (n = 7).
Conclusion: In our population 100% of malignant priapism would have been identified with a thorough history, examination and simple haematological testing. Computed Tomography of the chest, abdomen and pelvis should be considered in men with an abnormally low haemoglobin and/or any symptoms or signs that may suggest malignancy.
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