PSEUDOTUMORS of the orbit are tumors in the strict sense of the word but not in the sense of "neoplasm," the prefix "pseudo" being used to differentiate them from true neoplasms of the orbit. Ophthalmic pathologists should use the word "pseudotumor" only in this general sense and should qualify the diagnosis further by reporting pseudotumor inflammatory, pseudotumor granulomatous, pseudotumor cystic, pseudotumor cholesteatomatous, etc. If such a classification were adopted generally, much of the confusion concerning this term would be eliminated. In this paper, I shall use the term "pseudotumor" to refer to any tumor of the orbit which is not a true neoplasm, such as a carcinoma or cylindroma.
Pseudotumors of the orbit, though seldom reported, are rather common. Reese 1 in 1934 made a survey of 30 cases of orbital masses and found that 50% of the patients had had exenteration of the orbit for a supposed primary neoplasm which was proved histologically to be a chronic inflammatory
COWAN TW. ORBITAL PSEUDOTUMORS. AMA Arch Ophthalmol. 1951;46(4):390-402. doi:10.1001/archopht.1951.01700020401003