Most cases of malignancies appear to be sporadic, but some syndromes are associated with malignancies with germline variants. Herein, a child with an unusual association of oncocytic variant adrenocortical carcinoma (ACC) and rhabdomyosarcoma (RMS) was presented. An 18-month-old-boy was admitted with virilization of the genital area, penis enlargement and erection, which had begun six months earlier. Serum total testosterone (457 ng/dL; NR <10), androstenedione (3.35 ng/mL; NR <0.5) and dehydroepiandrosterone- SO4 (206 mcg/dL; NR<35) were above the normal ranges. Right adrenal mass was detected. After adrenalectomy, histopathological examination revealed an oncocytic variant ACC. Three-month after surgery, he then presented with 6x8 cm sized swelling of the left leg. Histopathological examination revealed embryonal RMS. Testing for tumor protein (TP53) variant by DNA sequence analysis was positive; however; fluorescence
in situ
hybridization analysis was negative. After chemotherapy and local radiotherapy, the patient is in good condition without tumor recurrence. Only about one-third of these tumors have a variant of TP53. This status also applies to other genetic variants related to cancer. However, a significant association of malignancies strongly suggests a problem in tumor suppressor genes or new variants. Another as yet unidentified suppressor gene may also be present and effective in this locus. The occurrence of ACC as a part of a syndrome and positive family history of malignancies in patients are clinically important. These patients and their families should be scanned for genetic abnormalities. The patient with ACC should be followed-up carefully for other tumors to detect malignancy early.