Melanocytoma

A melanocytoma is a rare pigmented tumor that has been described as a variant of the melanocytic nevus[1] and is a derivative of the neural crest.[2] The term "melanocytoma" was introduced by Limas and Tio in 1972.[3][4]

Histology

Histologically, the tumor is described by large, uniformly shaped polyhedral nevus cells that are pigmented and closely packed[5] Typically, it lacks signs of malignancy such as high mitotic rate, necroses or infiltrative growth.[6] Like the malignant melanoma, it shows an immunohistological profile with S-100 protein-, vimentin- and HMB-45-positive tumor cells.[6]

Optic melanocytoma
Further information: Optic nerve tumor

Most commonly the melanocytoma is found on or adjacent to the optic nerve[7] as the optical melanocytoma. The lesion can be found at any age. Location and size could lead to clinical symptoms.While the melanocytoma is generally considered to be a benign tumor,[7] it has a potential for growth, recurrence, and transformation to a malignant melanoma.[5] Because malignant transformation is rare, optical melanocytomas can usually be observed.[1] Thus, in asymptomatic patients, regular observation by fundoscopy is indicated, perhaps supported by ocular ultrasonography.[8][9][10]

Meningeal melanocytoma

The meningeal melanocytoma is found on the leptomeninges of the brain,[6][7] typically in the area of the base of the brain and brain stem,[2] or the spine.[4][11] Symptoms may be absent or related to growth and location. Like with the optic version, growth, recurrence, and malignant transformation are the main problems. Meningeal melanocytomas represent 0.06-0.1% of brain tumors.[12] In a 2003 review of 95 cases by Rahimi-Movaghar et al, 45 were intracranial (mostly supratentorial) and 50 spinal or along spinal roots.[13] The authors noted that the median age was 40 years for patients with intracranial and 49 for those with spinal tumors. Lesions were more common in women (57.9%). The review showed a recurrence rate of 26.3% and a death rate of 10.5% over 46 months.[13] A 2001 review by Rades et al concluded that complete resection is the best treatment.[14] If resection is incomplete, postoperative radiotherapy should be applied.

Differential diagnosis

Pigmented tumors raise the possibility of a malignant melanoma, a condition that may present diagnostic and therapeutic dilemmas.[9] In the differential diagnosis, schwannoma and meningioma with pigmentation are to be considered as well.[11]

Veterinary medicine

Melanocytomas have been described in animals, for instance, dogs and cats.[15][16]

See also

References
  1. Shields, Jerry A.; Demirci, Hakan; Mashayekhi, Arman; Eagle, Ralph C.; Shields, Carol L. (2006). "Melanocytoma of the Optic Disk: A Review". Survey of Ophthalmology. 51 (2): 93–104. doi:10.1016/j.survophthal.2005.12.011. ISSN 0039-6257. PMID 16500211.
  2. Sethi, Divya; Duhan, Amrita; Sen, Rajeev; Goyal, Vandana; Modi, Shilpi (2011). "Spinal meningeal melanocytoma". Asian Journal of Neurosurgery. 6 (2): 110–2. doi:10.4103/1793-5482.92176. ISSN 1793-5482. PMC 3277064. PMID 22347335.
  3. Limas C, Tio FO (1972). "Meningeal melanocytoma ("melanotic meningioma"). Its melanocytic origin as revealed by electron microscopy". Cancer. 30 (5): 1286–94. doi:10.1002/1097-0142(197211)30:5<1286::aid-cncr2820300522>3.0.co;2-v. PMID 4343293.
  4. Shanthi, Vissa; Ramakrishna, BA; Bheemaraju, VydehiVenkata; Rao, NandamMohan; Athota, Venkata RamanaMurthy (2010). "Spinal meningeal melanocytoma: A rare meningeal tumor". Annals of Indian Academy of Neurology. 13 (4): 308–10. doi:10.4103/0972-2327.74192. ISSN 0972-2327. PMC 3021939. PMID 21264144.
  5. Mohmad, Zalilawati; Aik Kah, Tan; Chui Yong, Ku; Wan Abdul Halim, Wan Haslina; Kong Yong, Then (2011). "Melanocytoma of the optic nerve head - a diagnostic dilemma". Clinics and Practice. 1 (3): 60. doi:10.4081/cp.2011.e60. ISSN 2039-7283. PMC 3981369. PMID 24765321.
  6. Schindler CU, Kuchelmeister K, Richter HP, Schachenmayr W (1998). "Das meningeale Melanozytom". Pathologe. 19 (4): 325–9. doi:10.1007/s002920050292. PMID 9746920.CS1 maint: multiple names: authors list (link)
  7. Reidy, James J.; Apple, David J.; Steinmetz, Robert L.; Craythorn, Judy M.; Loftfield, Katherine; Gieser, Stephen C.; Brady, Steven E. (1985). "Melanocytoma: Nomenclature, pathogenesis, natural history and treatment". Survey of Ophthalmology. 29 (5): 319–327. doi:10.1016/0039-6257(85)90107-9. ISSN 0039-6257. PMID 3992470.
  8. P. M. Sharma u. a.: Malignant transformation of optic disc melanocytoma? A clinical dilemma at presentation with a review of the literature. In: Ophthalmologica 216, 2002, S. 292–295. PMID 12207136 (Review).
  9. Timothy Murray, Timothy G. (2010). "Clinical imaging and high-resolution ultrasonography in melanocytoma management". Clinical Ophthalmology: 855. doi:10.2147/OPTH.S11891. ISSN 1177-5483. PMID 20714362.
  10. Lisker-Cervantes, Andrés; Ancona-Lezama, David Arturo; Arroyo-Garza, Luis Javier; Martinez, Jaime D.; Barreiro, Roberta Gomez Diaz; Valdepeña-López-Velarde, Victor Daniel; Morales-Canton, Virgilio; Moragrega-Adame, Eduardo (2017). "Ocular ultrasound findings in optic disk melanocytoma". Revista Mexicana de Oftalmología. 91 (6): 316–320. doi:10.1016/j.mexoft.2017.03.003. ISSN 0187-4519.
  11. Wang, F.; Li, X.; Chen, L.; Pu, X. (2007). "Malignant transformation of spinal meningeal melanocytoma. Case report and review of the literature". Journal of Neurosurgery. Spine. 6 (5): 451–4. doi:10.3171/spi.2007.6.5.451. PMID 17542513.
  12. Elazim, AhmedAbd; Elbadry, Rasha; Mohamed, Kazim; Issa, Mamdouh; Ayyad, Ali (2018). "Primary meningeal melanocytoma of the cerebellopontine angle associated with ipsilateral nevus of Ota: A case report". Surgical Neurology International. 9 (1): 245. doi:10.4103/sni.sni_235_18. ISSN 2152-7806. PMC 6293867. PMID 30613434.
  13. Rahimi-Movaghar, Vafa; Karimi, Mehrbod (2003). "Meningeal melanocytoma of the brain and oculodermal melanocytosis (nevus of ota): case report and literature review". Surgical Neurology. 59 (3): 200–210. doi:10.1016/S0090-3019(02)01052-2. ISSN 0090-3019. PMID 12681556.
  14. Rades, Dirk; Heidenreich, Fedor; Tatagiba, Marcos; Brandis, Almuth; Karstens, Johann Hinrich (2001). "Therapeutic options for meningeal melanocytoma". Journal of Neurosurgery: Spine. 95 (2): 225–231. doi:10.3171/spi.2001.95.2.0225. ISSN 1547-5654. PMID 11599841.
  15. Martens, A. L. (2007). "Unusual presentation of an anterior uveal melanocytoma in a 3-year-old poodle". The Canadian Veterinary Journal. 48 (7): 748–50. PMC 1899854. PMID 17824163.
  16. Wilcock B, Dubielzig RR, Render JA. Histological Classification of Ocular and Otic Tumors of Domestic Animals. In: Schulman FY, editor. WHO International Histological Classification of Tumors of Domestic Animals. IX. Armed Forces Institute of Pathology; Washington, D.C: 2002.
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