Citation: Cureus. 12(7):e9210, 2020 Jul 15..Journal: Cureus.Published: ; 2020ISSN: 2168-8184.Full author list: Cuevas Castillo FJ; Sujanani S; Chetram VK; Elfishawi M; Abrudescu A.UI/PMID: 32754413.Subject(s): IN PROCESS -- NOT YET INDEXEDInstitution(s): MedStar Washington Hospital CenterDepartment(s): Medicine/Internal MedicineActivity type: Journal Article.Medline article type(s): Case ReportsOnline resources: Click here to access onlineDigital Object Identifier: https://dx.doi.org/10.7759/cureus.9210 (Click here)Abbreviated citation: Cureus. 12(7):e9210, 2020 Jul 15.Abstract: Monckeberg medial calcific sclerosis (MCS) is an infrequent finding in the temporal artery and can clinically present almost indistinguishably from giant cell arteritis (GCA). To our knowledge, there have been only two case reports of suspected GCA found to be MCS only after a temporal artery biopsy (TAB). Herein, we present two cases. The first case is a 69-year-old female with hypertension, type-2 diabetes mellitus, and chronic headaches who presented with left temporal headaches and scalp tenderness. She had a prominently dilated, tortuous, and tender left temporal artery. Initial labs showed a leukocyte count of 11.1x103/L, erythrocyte sedimentation rate (ESR) of 29 mm/hr, and C-reactive protein (CRP) of 5.8 mg/L. The patient was started on prednisone 60 mg for presumptive GCA. Left TAB was negative for inflammatory changes, with findings consistent with MCS. Steroids were discontinued, and symptoms resolved. The second case is a 67-year-old male with hypertension, asthma, hyperlipidemia, status-post left eye cataract phacoemulsification, with intraocular lens insertion one-month prior, who presented with left eye blurriness in the inferior visual field and intermittent headache for 15 days. Left ophthalmoscopy showed retinal pallor and edema. Initial labs revealed ESR of 25 mm/hr, CRP of 11.2 mg/L, leukocyte count of 13.01x103/L. The patient was given solumedrol 120 mg once and prednisone 70 mg daily for presumptive GCA. Left TAB was negative for GCA but reported damaged elastic fibers by calcification consistent with MCS. Partial visual blurriness remained, and steroids were discontinued. This report accentuates the importance of MCS as a temporal GCA simulator. Physicians should be aware that TAB potentially changes management and may help surface underlying conditions. Copyright (c) 2020, Cuevas Castillo et al.