An unusual location of squamous cell carcinoma and a rare cutaneous infection caused by serratia marcescens on the tumoral tissue: A case report.

Rationale: Serratia marcescens (S. marcescens) is an opportunistic pathogen of the Enterobacteriaceae family. Although S. marcescens is known to cause sepsis, meningitis, endocarditis, urinary system and ocular infections, skin infections are sporadic. Squamous cell carcinoma (SCC) is the most aggressive skin cancer type that is often located in the head and neck region, and rarely in the scalp tissue. Patient concerns: An 89-years-old male patient was diagnosed with SCC three years ago. The frontal region of the skull showed an ulcerated tumor, irregular borders, and exophytic growth pattern. The destruction of the frontal bone made the vibrating brain tissue visible, and the lower part had haemopurulent flow. Diagnoses: Gram staining showed the proliferation of gram (-) bacilli. Bacteria were identified as non-pigmented S. marcessens in the wound culture. To the best of our knowledge, there have not been any cases reported with S. marcescens causing cutaneous infections on SCC. Therefore, our report is the first case in the literature. Interventions: According to the culture antibiogram, S. marcescens was ciprofloxacin sensitive. Consequently, 1000mg/day ciprofloxacin was initiated for 14 days. Outcomes: Purulent exudate in skin cancers may be caused by the nature of carcinoma tissue as well as the colonization of opportunistic pathogen microorganisms as seen in our patient. Lessons: Examination of the wound cultures and elimination of infections are critical in these cases.