case_images: PMC10484504_01
case_images: Skin pigmentation in the (A) right forearm, (B) left forearm, (C) left lower leg, (D) right lower leg, and (E) trunk.
case_images: fonc-13-1184738-g001.jpg
case_images: PMC10484504_01_fonc-13-1184738-g001.jpg
case_images: f1
case_images: Seven months later, the patient developed grayish pigmentation on the four limbs and trunk; these were especially prominent on the sunlight-exposed forearms ( Figure 1 ).
case_images: Histopathological examination and immunostaining finding of pigmented markers in the pigmented skin and bullous lesion. (A, B) Hematoxylin and eosin staining. (C, D) Fontana-Masson Staining. (E, F) HMB-45 staining.
case_images: fonc-13-1184738-g002.jpg
case_images: PMC10484504_01_fonc-13-1184738-g002.jpg
case_images: f2
case_images: Figures 2A, B ). Fontana-Masson staining for melanin revealed that the melanophages was distributed unevenly and generally present in the upper dermis ( Figures 2C, D ). Human Melanoma Black-45 (HMB-45) staining revealed decreased melanocyte numbers in both normal and clefting skin lesions ( Figures 2E, F ).
case_images: Immunostaining of specimens from the pigmented skin and bullous lesion. (A, B) Activated epidermal Langerhans cells present with CD1a. (C, D) Immunohistochemical staining of CD3. (E, F) Infiltrating CD4. (G, H) Infiltrating CD8.
case_images: fonc-13-1184738-g003.jpg
case_images: PMC10484504_01_fonc-13-1184738-g003.jpg
case_images: f3
case_images: T cells infiltrating into the epidermis and dermis; these findings indicated type IV hypersensitivity ( Figures 3A-H ). Thus, a clinicopathological diagnosis of ribociclib-induced phototoxicity, manifesting initially as dyschromia and subsequently as bullous dermatosis, was made.