To our knowledge, there are nine previous reports of patients with congenital scrotal agenesis (CSA), seven of which were bilateral, and unilateral in two, also named as hemiscrotal agenesis (HSA). Here, we report a male infant with the previously undescribed co-occurrence of HSA with cutis marmorata telangiectatica congenita (CMTC), and hydronephrosis due to vesicoureteral reflux, all of them on the left side. CMTC is a segmental vascular malformation usually attributed to mosaicism of a postzygotic mutation, whereas the mechanisms in the CSA involve a failure on the labioscrotal fold (LSF) development due to a localized 5α-reductase deficiency and/or androgen insensitivity. Since the skin with HSA was affected also by CMTC and by the fact that it exhibited lack of response to the topical testosterone treatment, all this suggests to us an androgen insensitivity mosaicism in our patient restricted to the left LSF, because skin with intact androgen receptors normally shows some type of response. Since CSA and/or HSA have been also seen in patients with PHACES, popitleal pterygium syndrome, or as part of a recently proposed familial entity with CSA (or agenesis of labia majora as its female counterpart), developmental delay, visual impairment, and moderate hearing loss, further reports could confirm this manifest genetic heterogeneity, highly evocative of somatic mosaicism in our patient.