Median raphe cysts are congenital uncommon lesions of the male genitalia developing along the median penile raphe from the meatus to the perineum . They result from “tissue trappings” during the intra-uterine process of closure of urethral or genital folds . Their clinical presentation is usually as a flesh to yellow solitary cyst, multiple cysts, or canal-like lesions in the ventral midline part of the penis and perineum . The penile shaft is the most frequent location, followed by subcoronal, scrotal and perineal areas . Cysts may sightly fluctuate in size throughout life . Three histologic patterns have been described: 1) urethral type lined with pseudostratified columnar epithelium, such as the urothelium; (2) epidermoid type, with squamous stratified epithelium; and (3) mixed type, with both epitheliae. The urethral type is the most frequent (70.1%) . Their diagnosis in children is probably underreported with a median age at diagnosis of 24,6 years . In fact, as cysts do not connect with urethra, up to 75% of cases are asymptomatic and infection is a rare complication [2, 6]. Other described complications are the cysts rupture and sexual interference in adulthood4. To prevent relapses and clinical symptoms, the majority of authors recommend surgical excision followed by primary closure1,5.
In case of infection, the most common organisms found in adults’ patient are Neisseria gonorrhoeae, Trichomonas vaginalis and Staphylococcus aureus . This case is unique in literature because the drainage liquid culture resulted positive for Serratia Marcescens, a common pathogen causing infections in patients affected by immunodeficiencies. In particular, chronic granulomatous disease (CGD) characterized by the defect in superoxide production, is the first immunodeficiency to rule out. Patients with CGD have an increased susceptibility to a narrow spectrum of pathogens including, beyond Serratia Marcescens, Staphylococcus aureus, Burkholderia cepacia complex, Nocardia species, Aspergillus species, Salmonella species and Mycobacterium tuberculosis. Most patient initially present within 5-years-old with lymphadenitis, abscesses especially of the liver and perianal region, pulmonary infections, osteomyelitis, and sepsis. Genitourinary and gastrointestinal systems are generally affected by granulomatous inflammation. The gold standard for diagnosing CGD is flowcytometric dihydrorhodamine (DHR) neutrophil respiratory burst assay to assess the nicotinamide adenine dinucleotide phosphate (NADPH) oxidase function [7, 8].