Metaplastic Ossification of the Temporal Artery with Osteoclast-Like Giant Cells: A Mimicker of Giant Cell (Temporal) Arteritis

Abstract

The clinical differential diagnosis of GCA includes other etiologies that can present similarly; however, temporal artery biopsy can discern the underlying pathology. Importantly, the identification of giant cells is not required for the diagnosis of GCA, and likewise, as our case shows, the finding of giant cells in the wall of a temporal artery does not always imply a diagnosis of GCA.

New Insights into the Roles of Monocytes/Macrophages in Cardiovascular Calcification Associated with Chronic Kidney Disease

“…Calcified cardiovascular lesions contain osteoclast precursors (i.e., monocytes/macrophages) and osteoblast-like VSMCs capable of secreting factors involved in osteoclast differentiation (such as receptor activator of nuclear factor kappa-B ligand (RANKL) and macrophage colony-stimulating factor (MCSF)) [10,80,81]. In vitro, RANKL expression by VSMCs induced the osteoclastic differentiation of monocytic preosteoclasts (RAW264.7 monocytes-macrophages or mice BMDMs in co-cultures)—an effect that was blocked by the addition of osteoprotegerin, a soluble decoy receptor for RANKL [10,82].…”

Comments on a Case Entitled “Gazing Into the Crystal Ball”

“…The readers point out several reported cases of histologically confirmed cases of calciphylaxis with ophthalmic involvement that did not have retinal vascular calcification (6)(7)(8)(9)(10)(11)(12)(13), and conversely, retinal arteriolar calcification reported without systemic calciphylaxis (14,15). We believe appearance of retinal vascular calcification/crystalline retinopathy and bilateral optic neuropathy in conjunction with profound vision loss is particularly unique in our case.…”

“…Similar retinal arteriolar calcification has been reported in 3 patients with ESRD, 2 of which did not have systemic calciphylaxis, but were more striking in appearance than the other (5–7). It is also noteworthy that 8 cases of vision impairment with clinically and histologically confirmed calciphylaxis in the ophthalmic literature do not report such a finding (6,8–14). Only one of these cases also had crystalline retinal deposits (6).…”

“…As the authors outlined, calciphylaxis has been suggested as the cause of a number of ischemic optic neuropathy cases (6,(8)(9)(10)(11)(12)(13)(14). Three of these erroneously diagnosed calciphylaxis based on temporal artery calcification alone (16)(17)(18).…”

Gazing Into the Crystal Ball Photo Essay: Response

“…The readers point out several reported cases of histologically confirmed cases of calciphylaxis with ophthalmic involvement that did not have retinal vascular calcification (6–13), and conversely, retinal arteriolar calcification reported without systemic calciphylaxis (14,15). We believe appearance of retinal vascular calcification/crystalline retinopathy and bilateral optic neuropathy in conjunction with profound vision loss is particularly unique in our case.…”