Urethral clear cell adenocarcinoma in an adult female: A rare case report

Abstract

Clear cell adenocarcinoma of the urethra is an extremely rare malignancy with a poor outcome, mainly affecting females in old age. We present the case of a 42-year-old female patient who presented with progressively worsening lower urinary tract symptoms, leading to a cystoscopy-guided core needle biopsy diagnosis of clear cell adenocarcinoma of the urethra. We will mainly discuss the cross-sectional imaging and pathological aspects of the case.

1 Introduction

Clear cell adenocarcinoma of the urethra (CCAU) is a rare primary malignancy of the urethra, overwhelmingly affecting females. The mean age at disease onset is 58 years. Lower urinary tract symptoms, hematuria, and a recurrent urinary tract infection are present. CCAU is present in the bladder base and urethra. When it occurs in the urethra, around half of the cases arise from an underlying urethral diverticulum.

The histological origin of CCAU has been debated, but new research suggests that it has a urological origin. This is supported by genetic and immunohistochemical study results that are similar to those of urothelial carcinoma. These include changes in chromosomes 3, 7, and 17, as well as positivity for CD10 and CK7. Histologically, there are 3 main forms, namely the papillary, tubulocystic, and diffuse forms. We also see nuclear pleomorphism, cytoplasmic clearing, and cellular structural variations consisting of hobnailing, cuboidal, and flat structures. ^, ^,

Cystoscopy investigation enables direct tumor visualization and sample acquisition. Imaging modalities consist of pelvic ultrasound, computed tomography (CT), and magnetic resonance imaging (MRI). They help to outline the full extent of the lesion in relation to adjacent organs.

1.1 Case presentation

A 42-year-old female presented with hesitancy and poor urinary flow, as well as abnormally increased urinary frequency and urge incontinence for a 1-year duration. Before coming to our hospital, she had received multiple antibiotic treatments for a suspected urinary tract infection. Other than her urination problems, she reported no previous history of chronic illnesses. On presentation, the patient had stable vital signs, and the physical examination was unremarkable. The baseline blood workup includes the complete blood count, renal function tests, and serum electrolytes within the reference range. Urinalysis revealed a turbid appearance, blood +2, and many RBCs per HPF.

The post-contrast abdominopelvic CT ( Fig. 1 ) revealed a 3.7 cm × 3 cm x 2.7 cm (TRxCCxAP) enhancing mass of the entire urethra with superior extension to the bladder base. The MRI ( Figs. 2 and 3 ) revealed T1W intermediate, T2W bright, and enhancing masses that completely filled the urethral lumen and completely obliterated the normal urethral signal stratum.

Both CT and MRI revealed no signs of abdominopelvic lymphadenopathy or solid organ secondaries. Upon cystoscopic evaluation, papillary growth filled the entire urethra, extending to the bladder neck. The bladder showed significant post-obstructive changes, including severe trabeculation and multiple diverticula. The bladder showed no growth, and both ureteric orifices were visible and appeared normal. We took multiple biopsy samples with transurethral resection and subjected them to pathological analysis. It was possible to see under a microscope that a lot of the tumor had mixed tubulopapillary and cribriform growth of highly pleomorphic cells, hobnailing, and cytoplasmic clear cell changes( Fig. 4 ). Immunohistochemical analysis ( Fig. 5 ) showed strong and diffuse CK7 and PAX8 positivity. The tumor was negative for CK20, CDX2, PSA, and P63.