INTRODUCTION
Intravascular papillary endothelial hyperplasia (IPEH) is a unique clinical entity i.e. a non-neoplastic intravascular lesion. This lesion was first described by Pierre Masson in 1923 (Masson 1923) then was termed IPEH (Clearkin & Enzinger 1976). So far, various researchers have struggled to define this unique condition with various terminologies such as Masson’s tumour, vegetating hemangioendothelioma, intravascular angiomatosis etc. This lesion should be differentiated from other malignant vascular neoplasm like angiosarcoma. We report an extremely rare case of IPEH that occurred in female urethra.
CASE REPORT
A 65-year-old Para 2, post-menopausal for 10 yrs not on hormone replacement therapy, presented with vaginal bleeding for one-week duration. There was no abnormal vaginal discharge or urinary symptoms. Her last Pap smear was 10 yrs ago. She was diagnosed to have hypertension and dyslipidaemia on treatment. Her aunt suffered from breast carcinoma.
Upon presentation, her blood pressure was 126/64mm Hg with pulse rate of 86 beats/min. There was no mass palpable abdominally. Perineal inspection revealed an atrophic vulva and vagina. There was a 3.0 x 3.0 x 4.0 cm growth seen surrounding the urethral meatus. Punch biopsy was taken and sent for histo-pathological examination (HPE).
HPE of the biopsy showed few segments of brownish tissue with aggregate diameter of 18 mm, macroscopically. Microscopically, there were few segments of haemorrhagic and oedematous fibrous stromal tissue. The stroma was hypocellular and oedematous, composed of multiple thombosed vessels with some of them displayed intravascular papillary endothelial cells proliferation (Figure 1). The endothelial cells expressed CD34 (Figure 2). There was no dysplasia or evidence of malignancy. The HPE was consistent with intravascular papillary epithelial cell proliferation (Masson’s tumour). She subsequently underwent examination under anaesthesia and full excision of the remaining lesion (Figure 3).
DISCUSSION
To date, the pathogenesis of IPEH remained poorly understood. Possible mechanisms include papillary proliferation of endothelial cell that subsequently degenerates and necrosis in the vascular lumen. Hashimoto et al. (1983) classified IPEH into 3 types. Type I IPEH (primary or pure form) occurs within the vascular spaces, where as, Type II is mixed form that occurs at pre-existing vascular lesion such as haemangioma, arteriovenous malformation or pyogenic granuloma. Lastly, Type III, the least common type, is found in extravascular space. All these lesions were closely associated with thrombus and thrombotic material (Pegado et al. 2015).
Most IPEH developed in head and neck, extremities and trunk (Hashimoto et al. 1983). It was rarely found in the genitourinary area especially urethra. Clinically, IPEH elsewhere usually presented as a firm tender mass overlying the skin or mucous membrane where as urethral IPEH presented with vaginal bleeding. To date, there are only four reports of urethral IPEH (Nevin et al. 2006; Barua & Munday 1983; Fernandes-Flores et al. 2003) (Table 1). All reported cases were post-menopausal women who were above 60 yrs.
Due to its non-specific clinical presentation; it poses a significant diagnostic challenge as malignant vascular neoplasm like angiosarcoma needs to be ruled out especially in elderly patient. Histopathologically, IPEH is associated with thrombi in an expanded vessel without evidence of mitotic activity, atypia or necrosis. The cells do not invade the perivascular spaces compared to angiosacrcoma. Immunochemically, IPEH reacts with various substances such as MSA, SMA, CD31 and CD34. Fortunately, angiosacrcoma can be differentiated with CD 105 staining as this molecule only overexpressed in angiosarcoma associated endothelial cells (Soares et al. 2008; Akdur et al. 2013).
The prognosis of IPEH is very good. Treatment includes local excision. Recurrence is extremely rare, though, it might occur at the site of previous vascular lesion or if the lesion is incompletely excised (Inaioz et al. 2001). The present patient presented with post-menopausal bleeding secondary to urethral IPEH. There was no evidence of recurrence after one year of excision.
IPEH at female urethra is an extremely rare occurrence. The lesion must be differentiated from other malignant vascular neoplasm. Surgical excision is warranted for histopathological examination as incorrect diagnosis may lead to over aggressive treatment.