Primary sellar melanocytic tumor mimicking hemorrhagic pituitary macroadenoma: Case report and literature review

Abstract

Primary melanocytic tumors of the central nervous system (CNS) are rare lesions, but primary sellar tumors are rarer. Only 10 cases have been reported, and they are often misdiagnosed as pituitary macroadenoma. We report the case of a 54-year-old Chinese man who developed progressive bitemporal hemianopsia and visual loss. Magnetic resonance imaging (MRI) revealed an intrasellar and suprasellar clouded lesion adhering to the optic chiasm, hypothalamus, and hypophyseal stalk that was suspected of being a hemorrhagic pituitary macroadenoma. Because of the atypically giant, hemorrhagic, and upward-growing lesion, an initial trans-sphenoidal approach failed, and subsequent transfrontal craniotomy was adopted to achieve macroscopically complete resection. Histopathologic findings revealed a benign melanocytic tumor. Despite an extensive search, no other primary or secondary site was found. Considering the relatively benign lesion, effective surgery, and potential significant consequences of radiotherapy, the patient received no further treatment and is still alive at the 7-year follow-up. Primary sellar melanocytic tumors are exceptional lesions that are difficult to diagnose before operating and/or obtaining pathological findings. The pathological classification and extent of surgical resection may play a key role in the prognosis. Once this type of lesion is suspected, the transfrontal approach may achieve preferable exposure and resection. Complete surgical resection may be sufficient for relatively benign lesions; otherwise, stereotactic fractionated radiotherapy is indicated. More cases should be reported to improve the treatment strategy.

Keywords::

• melanocytic tumor
• primary
• pituitary macroadenoma
• sellar
• transfrontal

Declaration of interest: The authors have no personal financial or institutional interest in any of the drugs, materials, or devices described in this article. This article is supported by a national clinical key specialty construction projects in China and technology program of Zhejiang province (2013C33123).

Supplementary material available online

Supplemental Video. This video shows the approach of transfrontal craniotomy to resect the primary sellar giant melanocytic tumor.

An initial trans-sphenoidal approach failed due to the atypically giant, hemorrhagic, and upward growing lesion, and subsequent transfrontal craniotomy was performed. The lesion appeared fibrous, rigid, and brownish-black with rich intratumoral hemorrhage. Careful surgical operation was performed through the fi rst and second gaps, offering adequate tumor exposure and blood control, making macroscopically complete resection possible. The optic chiasm, hypothalamus, and hypophyseal stalk were completely reserved.