Metastatic CIN3-like squamous carcinoma

Despite the major impact cervical screening has had on incidence and mortality of cervical cancer, it still poses a risk to women especially when the clinical presentation is unusual. When classification of histological features is also challenging, this adds to the risk of delayed diagnosis and subsequent suboptimal management. We report a case of squamous carcinoma with CIN3-like growth pattern, which metastasized to psoas muscle 13 years following cone biopsy reported as CIN3 with a small focus of microinvasion. This is an unusual case in several aspects: (a) it had the histological features of squamous carcinoma with CIN3-like growth pattern, a subvariant of cervical squamous carcinoma, which is often under-diagnosed as CIN3 with possible early stromal invasion, (b) the endometrial epithelium in the subsequent hysterectomy specimen was entirely replaced by similar pathology (CIN3-like growth pattern), (c) pathology of the distant metastasis, which occurred several years after hysterectomy, also revealed CIN3-like growth pattern. This case raises awareness of the entity of squamous carcinomas with CIN3-like growth pattern as well as the potential of cervical carcinomas to metastasize late and to unusual sites.