Animal-type malignant melanoma associated with nevus of Ota in the orbit of a Japanese woman

Abstract

We present a patient with an animal-type malignant melanoma associated with the nevus of Ota in the orbit who showed a good prognosis after a combination of orbital extirpation, chemotherapy, stereotactic radiotherapy, and gamma knife. A 42-year-old Japanese woman presented with two tumors, one pathologically diagnosed as right-sided intraconal animal-type malignant melanoma and the other intracranially, presumed to be of the same pathogenesis and both were considered to have arisen from the nevus of Ota. She underwent an extirpation of the orbit, chemotherapy (DAV therapy, which is a combination of dacarbazine, nimustine, and vincristine), stereotactic radiotherapy (54 Gy in 27 fractions), and gamma knife (marginal dose was 17 Gy, target volume was 0.2 ml). She has been alive for 33 months since the extirpation, with no sign of local recurrence, new metastasis, nor enlargement of the intracranial tumor. Not just combination therapy but also the low malignancy of animal-type melanoma may have contributed toward the good prognosis.

Melanoma arising in a nevus of Ito: novel genetic mutations and a review of the literature on cutaneous malignant transformation of dermal melanocytosis

“…A total of 10 arose within nevi of Ota and 3 in nevi of Ito . In addition to these cutaneous melanomas arising in association with nevi of Ota and Ito, over 40 cases of primary melanoma of the uveal tract (choroid, iris and ciliary body), orbital soft tissues, central nervous system, meninges and dura have been reported in association with nevi of Ota . We could not identify reports of malignant transformation of Mongolian spot.…”

Nevus of Ota with Intraoral Involvement: Case Report and Review of the Literature

“…In summary, we describe an unusual clinical presentation of a nevus of Ota. Although the possibility of malignant transformation from a nevus of Ota is low, the risk should be considered [27] and biannual followup is recommended to monitor sudden changes in color, ulceration or paresthesia [13]. In the context of nevus of Ota with oral involvement, it is important to consider that 17.8% of the cases can develop malignant tumors; thus, histopathology is essential to confirm the condition and to discard malignancy, notwithstanding its low frequency [23].…”

Animal-type melanoma: dog or wolf? A review of the literature and a case report

“…Rare cases of ATM have been described on the skin of genitalia as reported on a newborn on left major labium (Ref 22). Mucosal localisation of ATM has also been described on the tarsal conjunctive (Ref 23) as oral mucosal lentiginous melanoma with prominent pigment synthesis (Ref 24), or similar to the typical Ota nevus in the sclera (Ref 25).…”