Melanotic Xp11-associated tumor of the sigmoid colon: A case report

Table 1 Comparative features of melanotic Xp11 tumors and perivascular epithelioid cell tumors

	Melanotic Xp11 tumors	PEComas
Sex predilection	Females > males	Females > males
Age	Children and young adults, but may affect older adults	Middle age, but may affect children and older adults
Family history		Tuberous sclerosis
Site	Kidneys, uterus, ovaries, cervix, colon, pancreas, bladder, and pelvis	Genitourinary tract, viscera, skin, soft tissue, and bone
Histology	Epithelioid with clear cytoplasm	Spindled, epithelioid, or sclerosing
Melanin pigment	Usually present	Usually absent
Muscle marker expression	Usually absent	Usually present
Melanocytic marker expression	Present	Present
Epithelial marker expression	Absent	Absent
Molecular genetic alteration	Xp11 translocation; PSF-TFE3 fusion	Loss of TSC1 (9q34) or TSC2 (16p13.3) gene

PEComa: Perivascular epithelioid cell tumor.