Oral focal mucinosis: A multi‐institutional study and literature review

Abstract

Background: Oral focal mucinosis (OFM) is a rare benign condition of unknown etiology, considered the oral counterpart of cutaneous focal mucinosis. We report the clinicopathologic features of 21 cases of OFM in conjunction with a review of the literature. Methods: Clinical data were collected from the records of five oral and maxillofacial pathology services. All cases were evaluated by hematoxylin and eosin staining, histochemistry, and immunohistochemistry (vimentin, S-100, α-SMA, CD34, and mast cell). Results: The series comprised 14 females (66.7%) and seven males (33.3%), with a mean age of 48.2 ± 20.7 years (range: 8-77 years) and a 2:1 female-to-male ratio. Most of the lesions affected the gingiva (n = 6, 28.6%) and presented clinically as asymptomatic sessile or pedunculated nodules with fibrous or hyperplasic appearance. All cases were negative for S-100 protein, CD34, and α-SMA and positive for Alcian blue staining. Conservative surgical excision was the treatment in all cases, and there was only one recurrence. Conclusion: OFM is a rare benign disorder that is often clinically misdiagnosed as reactive lesions or benign proliferative processes. Dermatologists and pathologists should consider OFM in the differential diagnosis of soft tissue lesions in the oral cavity, mainly located in the gingiva. K E Y W O R D S connective tissue diseases, diagnosis, oral focal mucinosis, oral pathology 1 | INTRODUCTION Oral focal mucinosis (OFM) is considered to be the oral counterpart of cutaneous focal mucinosis (CFM) that likely develops due to an overproduction of hyaluronic acid by fibroblasts. 1-3 As a result, a well-demarcated myxomatous tissue positive for Alcian blue (pH 2.5) is observed microscopically; which may mimic other oral myxoid lesions, such as soft-tissue myxoma, fibrous hyperplasia with myxoid degeneration, nerve sheath myxoma (NSM), myxoid neurofibroma, and mucocele. 1

Case report: Sublingual mucinosis in a dog

“…In human the most common intraoral sites of OFM are gingiva (58.2%), palate (15.3%), and alveolar ridge mucosa (8.2%), while in our case the lesion is found in the sublingual mucosa ( 12 ).…”

“…In human medicine the term OFM was first introduced in 1974 by Tomich, et al ( 1 ) to describe lesions whose histopathological appearance was similar to the cutaneous counterpart. Since then, approximately 100 well-documented cases of OFM have been reported in the literature ( 12 ).…”

“…Studies have suggested that it is caused by the overproduction of HA by fibroblasts ( 1 , 13 ). Although, the underlying cause for this overproduction remains largely unknown, a predisposing role of local trauma has been hypothesized in people ( 12 , 13 ). The study of Cunha, et al ( 12 ) failed to identify any apparent involvement of local irritation or masticatory trauma in most cases; however, three cases had local trauma involvement.…”

“…Although, the underlying cause for this overproduction remains largely unknown, a predisposing role of local trauma has been hypothesized in people ( 12 , 13 ). The study of Cunha, et al ( 12 ) failed to identify any apparent involvement of local irritation or masticatory trauma in most cases; however, three cases had local trauma involvement. These data support the conclusion that at least a subset of OFM may be reactive in nature.…”

Intramuscular Myxoma of the Intrinsic Muscles of the Tongue: A Case Report with Literature Review

“…The findings of a multinodular growth pattern and epithelioid Schwann cells arranged in cords can distinguish nerve sheath myxoma from intramuscular myxoma. Oral focal mucinosis is non-neoplastic lesion that likely develops secondary to overproduction of hyaluronic acid by fibroblasts [ 37 ]. Fragmented and randomly arranged ropey collagen fibers seen in oral focal mucinosis can help to differentiate it from intramuscular myxoma.…”