A big benign pigmented skin lesion was found on her back again

A big benign pigmented skin lesion was found on her back again. it usually develops in the skin, mucosa, and choroid in the eye. In the central nervous system (CNS), melanocytes normally exist in the leptomeninges located on the inferior surface of the cerebrum and, the anterolateral surface of the brainstem and the spinal cord. Melanocytic lesions of CNS include melanocytosis, melanomatosis, melanocytoma, and malignant melanoma. Melanocytosis and melanomatosis are benign and involve diffusely leptomeninges and superficial brain parenchyma, which generally occur in the setting of dermatologic syndrome8). Melanocytoma is actually a solitary, benign and low-grade tumor that occurs mostly in the intradural extramedullary cervical or thoracic spine5). Malignant melanoma is a highly aggressive tumor with a CRA-026440 poor prognosis, which arises from melanoblasts6). Secondary or metastatic intracranial malignant melanoma is frequent in individuals with disseminated melanomas. However , primary intracranial leptomeningeal melanomatosis, also known as a meningeal variant of main intracranial malignant melanoma is usually rare. Its rarity may contribute to the large chance of misdiagnosis, especially in the cases without skin lesions. We report a rare case of primary leptomeningeal melanomatosis and review relevant literatures. == CASE REPORT == A 66-year-old female patient presented a headache that had been progressing over several months. The neurological examinations demonstrated no specific neurological deficits. The brain computed tomography (CT) (Fig. 1) showed diffuse high density lesions with multiple, branching, and linear enhancements in the foundation of the right temporal lobe. These non-contrast CT findings were just like those of subarachnoid hemorrhages (SAH). The brain magnetic resonance picture (MRI) (Fig. 2) exposed multiple, branching, and linear high signal intensity lesions on the T1-weighted image (WI), low signal intensity lesions on the T2-WI, and strong enhancements with all the same pattern. Spinal tapping for cytological examination of cerebrospinal fluid (CSF) was performed to rule out hemorrhage, infectious diseases and tumors. The cytological examination showed large cellularity, pleomorphic cells with abundant cytoplasm and black pigmentation, nuclear pleomorphism, prominent nucleoli, and seven mitoses per 10 high electrical power fields (HPFs). These tumor cells demonstrated strong immunoreactivity to HMB-45, S-100, and Melan-A. These histopathological findings are compatible with CRA-026440 those of malignant melanoma (Fig. 3). The whole body positron emission tomography CT (PET-CT) showed no abnormal findings. A biopsy showed the pigmented skin lesions around the back and the conjunctiva (Fig. 4) were benign pigmented nevi. == Fig. 1 . Brain CT shows diffuse high density lesion in the foundation of right temporal lobe which is comparable finding with subarachnoid hemorrhage on non-contrast image (A). Strong enhancements with multiple, branching, linear CRA-026440 pattern are seen in the same area (B). == == Fig. 2 . Brain MRI shows multiple, branching, linear high signal intensity lesions in the right temporal foundation on axial T1-WI (A), and also strong enhancements with same pattern are seen (B). These findings are mainly found in the horizontal and substandard surfaces from the temporal lobe on enhanced sagittal (C) and coronal T1-WIs (D). Low signal intensity lesions with same patterns are seen in the same location on axial T2-WI (E). == == Fig. 3. Pathological findings shows pleomorphic cells with considerable cytoplasm, considerable intracytoplasmic melanin pigments, nuclear pleomorphism, and prominent nucleoli (Papanicolaou stain, 1000). These tumor cells showed strong immunoreactivity to HMB-45, S-100, and SERK1 Melan-A on the immunohistochemical study. == == CRA-026440 Fig. 4. Photograph of skin lesion around the back. This lesion was confirmed because pigmented nevi through the biopsy. == == DISCUSSION == Primary CNS melanoma is usually rare, with only an approximately 1% incidence of all cases of melanomas2)whereas secondary intracranial melanomas are common. Melanocytes are derived from melanoblasts, which originate from the neural crest of the neuroectoderm during the embryonic period6). Malignant transformation of preexisting melanocytic precursor cells is considered the etiology of melanocytic tumors1, 11). Primary CNS melanocytic tumors can radiologically present a localized or nodular pattern and a diffuse or infiltrating pattern. The diffuse type is called melanomatosis, CRA-026440 which represents diffuse infiltrations into the subarachnoid space and the superficial brain without a solid mass2). The focal type is called melanocytoma, which is limited to a circumscribed pigmented mass. It has a better prognosis than the diffuse type because of the possibility of total excision by surgery2). In this case, diffuse enhancements were found in the temporary lobe with out definite mass and the cytological.