R P Singh, J Singh
bednar tumour, melanin, neck region, wide excision
R P Singh, J Singh. A Rare Bednar Tumour Of Neck. The Internet Journal of Pathology. 2013 Volume 15 Number 1.
Bednar tumour ( pigmented Dermatofibrosarcoma protuberans ) is a variant of dermatofibrosarcoma protuberans(DFSP)-constitute 5% of all DFSP-a relatively uncommon soft tissue neoplasm with intermediate to low grade malignancy rarely metastasizing to regional lymph nodes or distant sites but prone for local recurrence.
We report here in a case of 68year old female who presented with a huge recurrent Bednar tumour(40cm X 36cm x 26 cm) arising from neck region after a gap of five years of primary excision.
Review of previous studies and histopathological examination of recurrent lesion was suggestive of Bednar tumour. We performed a wide excision with 3 cm free skin margins. Soft tissue reconstruction was done to close the defect at the resected area.Recognition of this tumour is important because of excellent prognosis after adequate surgical excision.
Pigmented dermatofibrosarcoma protuberans or previously known as Pigmented storiform neurofibroma is a rare variant of DFSP ,described by BEDNAR in 19571.The histological picture shows melanin laden dendritic cells with spindle shaped cells in storiform pattern.The tumour mostly occurs on trunk,upper and lower extremities,few in head and neck region2..It is a slow growing,locally invasive-painless cutaneous multilobulated lesion, burn or surgical scar3 at the initial stage often the cause.
It has been shown that Giant cell Fibroblastoma has a close histogenic relationship to Dermatofibrosarcoma protuberans4 and it has been reported that Giant cell fibroblastoma can transform into DFSP5-7.We present here a case of massive Bednar tumour of neck region presenting five years after initial excision.
A 68 year old female was admitted with a huge painless nodular tumour
over the neck region. She gives history of insect bite at the same spot eight years
back following which a tumour developed over next one year slowly growing upto
four cm in diameter. The lesion was excised under local anaesthesia and histological
diagnosis revealed Dermatofibroma. She had another recurrence of the tumour two
year following the first excision which she neglected and the tumour gradually
progressed to a very large size.
The patient denied fever , chills, bony pain or any other constitutional
symptoms. On physical examination ,patient was not cachectic with no palpable
lymphadenopathy.Respiratory, CVS and GI exam was within normal limits.
Skin examination revealed 40 x 34 cm exophytic mass over neck region with
multiple soft protuberances of varying size none exceeding 8 cm,soft in consistency
with thin skin cover over certain areas with ulceration. The nodules appeared fixed
to the overlying skin but were mobile over the deep tissue.There was no other
positive finding on complete head and neck examination and there was no other
swelling elsewhere in the body.
Lab. Findings were within the normal limits.Chest X-ray was WNL.
Computed tomography ( CT ) revealed no invasion of the mass into deeper
A wide and deep excision with 3 cm margins of normal tissue all around
the lesion was performed. Grossly,the resected specimen measured 40 X 36X26 cm diameter with multiple discrete nodular mass,the greatest being 8 cm in diameter. The nodules were well circumscribed,had a firm consistency and showed a whorled pattern on cut section.
On histologic examination ,they were found to be composed of a uniform
population of fibroblast like cels,arranged in a storiform pattern . The cells had hyperchromatic oval to spindle shaped nuclei with low mitotic activity.The striking feature was presence of bipolar and multipolar dendritic cells with tentacle like processes emanating from nucleus .
Immunohistochemical study showed positive reaction to CD 34 and
VIMENTIN and negative for protein S-100 but melanin containing cells showed
positive for protein S-100.
The resected specimen showed tumour free margins. Soft tissue
reconstruction was done at the resected site of tumour.
Retrograde histological re-examination of the specimen obtained from the second excision of the recurrent tumour showed high expression of CD34 and revealed present tumour was actually a recurrence of this tumour.
The wound healed without any complication and the post operative course was uneventful,with no paraesthesia or skin sloughing at the reconstruction site.
The case presented here was DFSP ,which was initially mistaken to be
dermatofibroma.Dermatofibromas composed predominantly of fibroblasts extending
into the subcutaneous tissue are difficult to distinguish from dermatofibrosarcoma
protuberans8 though the patterns are different.
Bednar tumour account for less than 5 % of all DFSP9 and more common
in Black male population .Different theories have been given regarding origin of
Pigment laden cells .Dual cell origin suggests CD 34 positive spindle cells of
Mesenchymal and pigmented cells of neuroectodermal origin10.
In the case reported here correct clinical diagnosis was not reached initially
but only later on recurrence after subjecting to histopathological and
immunohistochemical studies.Condensation of connective tissue at the periphery
may give a false appearance of encapsulation but tumour may extend well beyond
margins11. We need to be aware of this condition12 and confirm histological
diagnosis before excision.
Recurrence are due to inadequate excision with tumour extending to deep
resection margin. With recurrence the lesion becomes less well differentiated13 and
chances of metastasis increases.Though rare,dissemination occurs by hemategenous
route and rarely lymphatically . The principal site being lungs though
bones,liver,pancreas,stomach,intestine,thyroid and brain may be involved
Surgery with a safety margin of 3 cm including the underlying fascia
serves good with Computerized tomogram helpful in deciding the line of incision to
prevent recurrence or metastasis.Mohs micrographic surgery14 has maximum
oncologic effectiveness and is the accepted treatment of choice.
Chemotherapy is not used in treatment while radiotherapy can be used as
adjunct to surgery in cases with positive resection margins.Molecular targeted
therapy and Imatinib may provide alternative treatment to unresectable tumours or
adjunctive treatment in addition to surgery.
In short ,Bednar tumour is a rare tumour.Painless ,cutaneous and
multilobulated lesion should arouse suspicion of this tumour and core or incision
biopsy should aim at pre-operative histologic diagnosis.Adequate excision will avoid
recurrence and excellent prognosis.