dermatofibrosarcoma protuberans ( dfsp ) is a rare slow - growing soft tissue neoplasm arising in the dermis . it usually occurs in the trunk or extremities but can involve the head and neck particularly the scalp . while often locally aggressive and frequently recurrent , metastases are rarely reported . relatively little has been reported in the radiology literature regarding the imaging features of dfsp of the head and neck . we describe a case of dfsp of the frontal scalp with fibrosarcomatous degeneration and lung metastasis . a 27-year - old female initially presented with painful swelling over the left eye which she first noticed 5 years earlier after minor trauma . she described an acute increase in pressure and pain in the lesion associated with headaches . on physical exam , a fluctuant mildly tender 8-cm mass was noted arising from the left forehead . after obtaining contrast - enhanced computed tomography ( ct ) , she was referred to plastic surgery , and 1 month later underwent wide local excision to the periosteum with 1 cm surgical margins . histopathological examination and immunohistochemical analysis were consistent with dfsp demonstrating areas of low - grade fibrosarcomatous transformation ; surgical margins were positive . the patient was scheduled for postoperative chemotherapy with imatinib , but failed to return for treatment . eight months later , she presented again after multiple episodes of bleeding from a recurrent left forehead mass . mri was obtained during admission [ figure 1 ] , and she subsequently underwent repeat wide local excision to obtain negative margins and a selective neck dissection . pathology was positive for recurrent dfsp with no evidence of tumor involvement in resected lymph or glandular tissue . concurrent chemoradiation therapy was planned , but the patient was again lost to follow - up . ( a ) axial t1 pre - contrast image demonstrates a large exophytic mass slightly hypointense to gray matter which has recurred within the left frontal scalp . ( b ) the mass is predominantly t2 hyperintense and demonstrates prominent heterogeneous enhancement after gadolinium on ( c ) axial and ( d ) coronal t1 post - contrast images . areas of central necrosis or hemorrhage are noted . two years later , the patient presented with a several week history of left - sided chest discomfort , cough , and shortness of breath . physical examination revealed a third recurrence of her frontal scalp tumor now measuring 12 cm with extensive superficial ulceration . repeat mri of the head [ figure 3 ] and ct of the thorax [ figure 4 ] demonstrated new pulmonary metastasis . she again underwent debulking of her scalp lesion and is currently being followed by otolaryngology and oncology with plans for possible repeat chemotherapy . ( a ) patient photograph and ( b ) corresponding saggital t1 post - contrast mri demonstrating the recurrent dfsp which is larger , and more ulcerated than previously with continued heterogeneous enhancement . ( a ) axial and ( b ) coronal post - contrast ct images of the chest demonstrate a large round mass with mild enhancement in the right lung centered in the right middle lobe and causing mass effect on the adjacent right atrium . first described in 1924 , dermatofibrosarcoma protoberans ( dfsp ) is a rare neoplasm of spindle cells arising in the dermis , usually in the trunk or extremities . its estimated incidence in the united sates is 4.5 cases per million per year and it accounts for approximately 6% of soft tissue sarcomas . although more common in young and middle aged adults , tumors can occur at any age and involve any body part.overall 5-year recurrence - free survival rate for each group has been reported as 81% in standard dfsp and 28% , dfsp with fibrosarcomatous degeneration . metastases do occur but are rare , occurring in < 10% of cases , but most often after local recurrence . lung involvement is most common with metastasis to the abdomen and local lymph nodes also being reported . imaging of dfsp is usually performed to assess local extent of the lesion as well as to identify any distant metastasis , and may assist in surveillance for recurrence . in the case presented , initial contrast enhanced ct [ figure 2 ] demonstrated a rounded protuberant heterogeneously enhancing mass arising from the left frontal scalp . mri of her recurrent tumor showed a large mass predominantly hypointense on t1 and hyperintense on t2 with heterogeneous enhancement after gadolinium . areas of central necrosis or hemorrhage were evident with extensive superficial ulceration [ figures 1 and 3 ] . contrasted ct of the chest during the patient 's third admission , revealed a large , rounded mass filling the majority of the right middle lobe and compressing the right heart representing a lung metastasis [ figure 4 ] . axial ct head ( a ) without and ( b ) with contrast demonstrate a large protuberant soft tissue mass arising from the left frontal scalp . the mass enhances heterogeneously after contrast with areas of central hypovascularity but no invasion of the calvarium . the ct and mr characteristics of dfsp were previously described by kransdorf and meis - kindblom in a series of 11 patients of which only one had a scalp lesion . in their study , most tumors were nodular or lobular lesions with attenuation similar to muscle and moderate inhomogeneous enhancement . on mr imaging , t1 low signal and t2 high signal were consistent features with enhancement seen after gadolinium . fibrosarcomatous areas may tend to be more necrotic and account for some of the heterogeneity seen on contrast - enhanced mr and ct scans . torreggani et al , in a series of 10 cases of dfsp of the trunk and extremities , also make the case for utilizing stir ( or other t2 fat saturated ) sequences to image these lesions . they reported several cases where mass was difficult to visualize on conventional t2 sequences due to the similar signal intensity of adjacent subcutaneous fat . older imaging techniques with catheter - based angiography have shown dfsp to be mildly to moderately hypervascular . bone scintigraphy has also been occasionally used in evaluation of these tumors and in three cases showed increased uptake of the radiopharmaceutical on delayed imaging . clinically , dfsp initially presents as a cutaneous pink to red - bluish painless plaque which grows more nodular with time . larger tumors may ulcerate and tend to be superficially mobile but fixed to the deeper structures such as muscle or fascia . slow tumor growth is characteristic and there is often a delay in diagnosis as patients can ignore the lesion for some time due to its indolent nature . lesions most commonly arise in the trunk with the extremities being the next most common site followed by the head and neck . there is also a slight male predominance and its incidence in african americans is almost twice that of caucasians . histolopathogically , dfsp shows a distinct  storiform  or  cartwheel  arrangement of uniform appearing fibroblasts [ figure 5 ] . immunohistochemical staining demonstrates strong positivity for cd34 ( sensitivity 84 - 100% ) and vimentin . dfsp can rarely present as a more aggressive fibrosarcomatous variant which occurs in around 10 - 15% of cases . patients with this more aggressive variant tend to be more prone both to local recurrence and distant metastasis . currently only around 150 cases of transformed dfsp have been reported and of these 13% had distant metastasis . ( a ) h and e stain demonstrating spindle - type cells with areas of classic  storiform  or  cart wheel  pattern . ( b ) immunostain for cd34 shows predominantly strong positivity but areas with loss of cd34 immunopositivity representing fibrosarcomatous transformation are also present ( arrow ) . standard treatment of dfsp is wide local excision with margins of at least 2 cm and many now advocate mohs micrographic surgical technique as achieving better results.[911 ] while the prognosis is excellent with complete resection , there is a marked tendency to recur if adequate surgical margins are not obtained . radiotherapy also has a role in treatment as the tumor has been shown to be radiosensitive ; chemotherapy with selective tyrosine kinase inhibitory such as imatinib mesylate has also shown good results .   in conclusion , dfsp is a rare tumor with a classic clinical presentation . while imaging features are often suggestive but not specific , cross - sectional techniques , particularly mr , can aid in clearly delineating the anatomic structures involved and rule out invasion of deep structures . while metastases are rare , in patients with fibrosarcomatous degeneration and multiple recurrences , surveillance imaging for metastasis may play a role first described in 1924 , dermatofibrosarcoma protoberans ( dfsp ) is a rare neoplasm of spindle cells arising in the dermis , usually in the trunk or extremities . its estimated incidence in the united sates is 4.5 cases per million per year and it accounts for approximately 6% of soft tissue sarcomas . although more common in young and middle aged adults , tumors can occur at any age and involve any body part.overall 5-year recurrence - free survival rate for each group has been reported as 81% in standard dfsp and 28% , dfsp with fibrosarcomatous degeneration . metastases do occur but are rare , occurring in < 10% of cases , but most often after local recurrence . lung involvement is most common with metastasis to the abdomen and local lymph nodes also being reported . imaging of dfsp is usually performed to assess local extent of the lesion as well as to identify any distant metastasis , and may assist in surveillance for recurrence . in the case presented , initial contrast enhanced ct [ figure 2 ] demonstrated a rounded protuberant heterogeneously enhancing mass arising from the left frontal scalp . mri of her recurrent tumor showed a large mass predominantly hypointense on t1 and hyperintense on t2 with heterogeneous enhancement after gadolinium . areas of central necrosis or hemorrhage were evident with extensive superficial ulceration [ figures 1 and 3 ] . contrasted ct of the chest during the patient 's third admission , revealed a large , rounded mass filling the majority of the right middle lobe and compressing the right heart representing a lung metastasis [ figure 4 ] . axial ct head ( a ) without and ( b ) with contrast demonstrate a large protuberant soft tissue mass arising from the left frontal scalp . the mass enhances heterogeneously after contrast with areas of central hypovascularity but no invasion of the calvarium . the ct and mr characteristics of dfsp were previously described by kransdorf and meis - kindblom in a series of 11 patients of which only one had a scalp lesion . in their study , most tumors were nodular or lobular lesions with attenuation similar to muscle and moderate inhomogeneous enhancement . on mr imaging , t1 low signal and t2 high signal were consistent features with enhancement seen after gadolinium . fibrosarcomatous areas may tend to be more necrotic and account for some of the heterogeneity seen on contrast - enhanced mr and ct scans . torreggani et al , in a series of 10 cases of dfsp of the trunk and extremities , also make the case for utilizing stir ( or other t2 fat saturated ) sequences to image these lesions . they reported several cases where mass was difficult to visualize on conventional t2 sequences due to the similar signal intensity of adjacent subcutaneous fat . older imaging techniques with catheter - based angiography have shown dfsp to be mildly to moderately hypervascular . bone scintigraphy has also been occasionally used in evaluation of these tumors and in three cases showed increased uptake of the radiopharmaceutical on delayed imaging . clinically , dfsp initially presents as a cutaneous pink to red - bluish painless plaque which grows more nodular with time . larger tumors may ulcerate and tend to be superficially mobile but fixed to the deeper structures such as muscle or fascia . slow tumor growth is characteristic and there is often a delay in diagnosis as patients can ignore the lesion for some time due to its indolent nature . lesions most commonly arise in the trunk with the extremities being the next most common site followed by the head and neck . there is also a slight male predominance and its incidence in african americans is almost twice that of caucasians . histolopathogically , dfsp shows a distinct  storiform  or  cartwheel  arrangement of uniform appearing fibroblasts [ figure 5 ] . immunohistochemical staining demonstrates strong positivity for cd34 ( sensitivity 84 - 100% ) and vimentin . dfsp can rarely present as a more aggressive fibrosarcomatous variant which occurs in around 10 - 15% of cases . patients with this more aggressive variant tend to be more prone both to local recurrence and distant metastasis . currently only around 150 cases of transformed dfsp have been reported and of these 13% had distant metastasis . ( a ) h and e stain demonstrating spindle - type cells with areas of classic  storiform  or  cart wheel  pattern . ( b ) immunostain for cd34 shows predominantly strong positivity but areas with loss of cd34 immunopositivity representing fibrosarcomatous transformation are also present ( arrow ) . standard treatment of dfsp is wide local excision with margins of at least 2 cm and many now advocate mohs micrographic surgical technique as achieving better results.[911 ] while the prognosis is excellent with complete resection , there is a marked tendency to recur if adequate surgical margins are not obtained . radiotherapy also has a role in treatment as the tumor has been shown to be radiosensitive ; chemotherapy with selective tyrosine kinase inhibitory such as imatinib mesylate has also shown good results .   in conclusion , dfsp is a rare tumor with a classic clinical presentation . while imaging features are often suggestive but not specific , cross - sectional techniques , particularly mr , can aid in clearly delineating the anatomic structures involved and rule out invasion of deep structures . while metastases are rare , in patients with fibrosarcomatous degeneration and multiple recurrences , surveillance imaging for metastasis may play a role .
dermatofibrosarcoma protuberans is a rare locally aggressive cutaneous tumor of intermediate malignancy . 
 it is a slow - growing neoplasm with a marked propensity to recur after resection . 
 head and neck involvement is unusual and distant metastases are quite rare but tend to be more frequent in tumors that undergo fibrosarcomatous degeneration . 
 we present the imaging and corresponding histopathology in a case of dermatofibrosarcoma protuberans of the scalp demonstrating fibrosarcomatous degeneration and lung metastasis .