cutaneous mucinoses refer to disorders with abnormal accumulation of mucin in the skin in a diffuse or focal pattern . mucin is an amorphous material that is part of the extracellular matrix with hyaluronic acid as the most important component of dermal mucin . the latter ones may be associated with systemic disorders such as autoimmune diseases , diabetes mellitus , paraproteinemia or altered thyroid function . cutaneous focal mucinosis ( cfm ) is a localized form of cutaneous dermal mucinosis clinically presenting as an asymptomatic skin - colored papule or nodule that occurs anywhere on the body or in the oral cavity . the etiopathogenesis of cfm is unclear , but it is thought to represent a reactive and not a neoplastic lesion . although trauma has been suspected as a triggering factor , it has never been proven in cases of cfm . we report 2 patients with trauma - induced cfm arising at an unusual site , i.e. the mammary areola , and discuss the differential diagnoses . the first patient was an otherwise healthy 47-year - old man with a solitary , skin - colored nodular lesion of 2 cm in diameter at the margin of the right areola ( fig . the medical history did not reveal other skin disorders except for a genital wart on the mons pubis . previous folliculitis had occurred and laser epilation had been performed in the area in which the nodular lesion on the areola developed . histopathology revealed circumscribed abundant dermal mucin deposits in a polylobulated pattern without an increased number of fibroblasts or capillaries ( fig . immunohistochemistry showed partial expression of fxiiia by 30% of the stromal cells , but no reactivity for cd34 , smooth muscle- actin ( sma ) , desmin , cd68 and s-100 . hematologic and serologic tests as well as radiologic examination did not show any abnormalities ; in particular , there were no signs of thyroid dysfunction , hypergammaglobulinemia or underlying breast carcinoma . the second patient was a 30-year - old man who presented with a 3 months ' history of a solitary , round , translucent , asymptomatic white exophytic nodule with a bluish hue on the right areola ( fig . he had worn a nipple ring piercing for 3 years only on the right side . he decided to remove it because of relapsing episodes of infectious dermatitis that had been treated with topical antibiotics . the lesion started a couple of weeks after the ring piercing had been removed with progressive enlargement . histopathology showed a polypoid , dome - shaped dermal nodule with abundant mucin filling the dermis , but not extending into the subcutis ( fig . fxiiia+ cells accounted for up to 20% of stromal cells positive for vimentin , and a few dermal dendritic cells were also positive for cd34 . complete blood count , thyroid function tests , serum immunoglobulins , antinuclear antibody , and dna antibody studies were done to rule out underlying systemic disease , and all results were normal or negative . cfm was first described as a separate entity by johnson and helwig in 1966 who also defined the histologic criteria for the diagnosis . it is characterized by an asymptomatic , elevated , whitish or skin - colored papule or nodule that is usually solitary and detected on the face , trunk or extremities , but not in proximity of the joints of the hands , wrists or feet . occasionally , cfm has been reported to occur as a soft fibroma - like polyp or a plaque - like lesion . contrary to other forms of primary mucinoses , cfm is usually not associated with systemic manifestations . , however , reported a case of multiple cfm with hypothyroidism and myxedema . moreover , cfm was described in association with other forms of mucinoses such as scleromyxedema and reticular erythematous mucinosis . interestingly , multiple focal cutaneous mucinoses have been considered as a side effect of anti - tnf- therapy in a case report . the histology is essential for the diagnosis and shows a diffuse ill - defined dermal accumulation of mucin sparing subcutaneous tissue , with a normal or slightly increased number of fibroblasts and absence of inflammation . spindle - shaped fibroblasts are the predominant cell type , with occasional admixed factor xiiia+ dendritic cells the cause of cfm is unknown but it is thought to be a reactive lesion arising as a result of the dysfunction of fibroblasts in a circumscribed area . chronic antigenic stimulation , inflammation , and viral infections could also account for the observed features . several recent studies have examined the relationship of cd44 receptor expression to dermal hyaluronate mucin accumulation , but trauma has never been explicitly reported as a triggering factor . in our cases , a history of trauma preceded the development of cfm in both patients . in the first patient , laser - based epilation of hairs and previous folliculitis in the nipple area and in the second patient this form of mucinoses may occur anywhere on the skin , but the mammary areola represents a very unusual localization . to the best of our knowledge , only one case of cfm at the nipple has been reported in the literature . an unusually large size of 2 cm was seen in our first case while cfm typically measures less than 1 cm in diameter . differential diagnosis of cfm includes benign and malignant neoplasms with myxoid stroma , such as angiomyxoma , neurothekeoma , nerve sheath myxoma and myxofibrosarcoma . histologically , a well - circumscribed lesion in the dermis with extension into the subcutis is found , which contains abundant mucin , fibroblasts of variable size and shape , multinucleated histiocytic giant cells as well as an increased number of small capillary vessels . in contrast to cfm , angiomyxoma displays a higher vascularity and expression of sma by the fibroblastic stromal cells . whereas cfm is usually less than 1 cm in diameter and ill - defined , angiomyxoma ( or myxoma ) measures between 1 and 5 cm in most cases and shows a well - defined , lobulated architecture . the lack of an increased number of vessels as well as the lack of sma expression argues against angiomyxoma in both of our patients . neurothekeoma is a benign neoplasm with a myxoid variant displaying a lobulated , frequently septated proliferation of fibroblasts embedded in a mucinous stroma . nerve sheath myxoma is mostly located on the hand and fingers and involves the dermis and/or subcutis . a multilobular tumor mass with abundant myxoid matrix and s-100 + schwann cells it is characterized by a mucinous tumor stroma and spindle - shaped tumor cells with nuclear pleomorphism and mitotic activity . the cellularity and the phenotype of the tumor cells allow to distinguish cfm from the above - discussed soft tissue tumors . surgical excision , which is the treatment of choice for cfm , was performed in both of our patients resulting in complete remission without recurrence . in summary , we reported two cases of trauma - related cfm arising at an unusual site such as the mammary areola . cfm has to be distinguished from benign and malignant neoplasms characterized by mucinous tumor stroma .
cutaneous focal mucinosis ( cfm ) is a localized form of cutaneous dermal mucinosis clinically presenting as an asymptomatic skin - colored papule or nodule . 
 the etiopathogenesis of cfm is unclear , but it is thought to represent a reactive lesion . although trauma has been suspected as a triggering factor , it has never been proven in cases of cfm . 
 we report 2 male patients with trauma - induced cfm arising at the mammary areola , which is an unusual site for cfm . both male patients presented with a solitary nodular lesion of up to 2 cm in diameter at the right areola . 
 histology was characterized by circumscribed abundant dermal mucin deposits in a polylobulated pattern without an increased number of fibroblasts or capillaries and with absence of an inflammatory infiltrate . 
 alcian blue stain at ph 2.5 highlighted the mucin deposits . 
 immunohistochemistry showed partial expression of fxiiia by 30% of the stromal cells , but no reactivity for cd34 , smooth muscle actin , desmin , cd68 and s-100 . 
 a history of trauma ( laser - based epilation , piercing ) preceded the development of cfm in both patients . 
 surgical excision resulted in complete remission without recurrence . 
 follow - up in both our patients did not reveal recurrences . 
 cfm has to be distinguished from benign and malignant myxoid neoplasms .