IMAGES FOR SURGEONS ANZJSurg.com
A case of peritoneal mesothelioma masquerading as a urachal mass A 71-year-old man presented for urological assessment with a 4-month history suprapubic pain. The pain was described as dull and also had an element of renal colic. It was associated with microscopic haematuria and significant weight loss of 20 kg. Routine bloods, prostate-specific antigen and urine cytology were unremarkable. A computed tomography of the abdomen and pelvis revealed a large calcified mass adjacent to the bladder wall initially thought to be a large residual urarchal cyst. There was no invasion of the pelvic wall. However, because of the degree of calcification, the mass was deemed to be suspicious of urachal carcinoma (Fig. 1). Cystoscopy, however, showed a normal bladder with no evidence of dome involvement. Laparotomy was performed for excision of the mass. At laparotomy, a mass was revealed in the lower pelvis, adherent to the right pelvic and femoral vessels. Tumour debulking, with removal of a soft tissue mass 110 × 85 × 90 mm in size and partial cystectomy was performed. Histopathology revealed a high-grade, poorly differentiated mesothelioma with spindle cell morphology, showing malignant heterologous elements because of osteosarcomalike bone formation. The specimen stained positive for caltretin and pancytokeratin. There was involvement of the margin and lymphovascular and perineural infiltration. The patient recovered from his laparotomy and was referred to radio-oncology for palliative radiotherapy. Given the diagnosis, further history was obtained. There is a glancing history of asbestos exposure, in that the patient performed home renovations about 30 years ago. He was thus also referred to the Dust Diseases Board.
Fig. 1. Calcified mass found on computed tomography.
© 2013 Royal Australasian College of Surgeons
Malignant mesothelioma is a primary tumour of the serous membranes. It is a rare tumour, affecting as few as two people per million.1 The most common site of origin is the pleura (65–70%), but it may also arise from the peritoneum (30%). More rarely, it may arise from the pericardium or tunica vaginalis of the testes.2 Malignant peritoneal mesothelioma (MPM) predominates in older men in their fifth and sixth decades. Patients may present with non-specific symptoms such as abdominal pain, ascites and marked weight loss.1 MPM is a disease that combines the tragedy of poor prognosis and difficult diagnosis. The rarity of occurrence, vague symptoms and spectrum of disease presentation makes the diagnosis of MPM difficult. It is often diagnosed in advanced stages because of the variety of radiological and clinical findings.3 The urachus is an embryological remnant connecting the apex of the bladder to the umbilicus. During development, the urachus eventually undergoes fibrosis to form a non-patent, fibromuscular strand. However, in rare cases, a defect in this process may occur, giving rise to an intraabdominal mass such as an urachal cyst (1/5000 births) or urachal carcinoma (
A case of peritoneal mesothelioma masquerading as a urachal mass A 71-year-old man presented for urological assessment with a 4-month history suprapubic pain. The pain was described as dull and also had an element of renal colic. It was associated with microscopic haematuria and significant weight loss of 20 kg. Routine bloods, prostate-specific antigen and urine cytology were unremarkable. A computed tomography of the abdomen and pelvis revealed a large calcified mass adjacent to the bladder wall initially thought to be a large residual urarchal cyst. There was no invasion of the pelvic wall. However, because of the degree of calcification, the mass was deemed to be suspicious of urachal carcinoma (Fig. 1). Cystoscopy, however, showed a normal bladder with no evidence of dome involvement. Laparotomy was performed for excision of the mass. At laparotomy, a mass was revealed in the lower pelvis, adherent to the right pelvic and femoral vessels. Tumour debulking, with removal of a soft tissue mass 110 × 85 × 90 mm in size and partial cystectomy was performed. Histopathology revealed a high-grade, poorly differentiated mesothelioma with spindle cell morphology, showing malignant heterologous elements because of osteosarcomalike bone formation. The specimen stained positive for caltretin and pancytokeratin. There was involvement of the margin and lymphovascular and perineural infiltration. The patient recovered from his laparotomy and was referred to radio-oncology for palliative radiotherapy. Given the diagnosis, further history was obtained. There is a glancing history of asbestos exposure, in that the patient performed home renovations about 30 years ago. He was thus also referred to the Dust Diseases Board.
Fig. 1. Calcified mass found on computed tomography.
© 2013 Royal Australasian College of Surgeons
Malignant mesothelioma is a primary tumour of the serous membranes. It is a rare tumour, affecting as few as two people per million.1 The most common site of origin is the pleura (65–70%), but it may also arise from the peritoneum (30%). More rarely, it may arise from the pericardium or tunica vaginalis of the testes.2 Malignant peritoneal mesothelioma (MPM) predominates in older men in their fifth and sixth decades. Patients may present with non-specific symptoms such as abdominal pain, ascites and marked weight loss.1 MPM is a disease that combines the tragedy of poor prognosis and difficult diagnosis. The rarity of occurrence, vague symptoms and spectrum of disease presentation makes the diagnosis of MPM difficult. It is often diagnosed in advanced stages because of the variety of radiological and clinical findings.3 The urachus is an embryological remnant connecting the apex of the bladder to the umbilicus. During development, the urachus eventually undergoes fibrosis to form a non-patent, fibromuscular strand. However, in rare cases, a defect in this process may occur, giving rise to an intraabdominal mass such as an urachal cyst (1/5000 births) or urachal carcinoma (
