imaging findings , even with computed tomography ( ct ) , of such tumors are rarely described in literature .
f-18 fluorodeoxy glucose positron emission tomography / computed tomography ( f-18 fdg pet / ct ) is emerging as a useful modality in assessment of genito - urinary malignancies .
f-18 fdg pet / ct findings in penile leimyosarcoma have not been reported in literature .
we present here a case of penile leiomyosarcoma with emphasis on findings on f-18 fdg pet / ct with histopathology correlation .
a 47-year - old male presented with a palpable penile mass , with rapid growth over a period of 1 month .
he was examined at an outside center and an incision biopsy of the tumor was done that revealed penile leiomyosarcoma .
he was later referred to our institute , a tertiary care center , for further management . on examination of the patient at our institute
, the patient was found to have 2  2 cm a typical nodular lesion in the proximal penile shaft .
review of the histopathology examination after biopsy revealed tumor composed of spindle cells with hyperchromatic nuclei , inconspicuous nucleoli , and frequent mitoses .
tumor cells also stained positive for smooth muscle antigen ( sma ) consistent with diagnosis of leiomyosarcoma of penis [ figures 1c and 1d ] .
as a part of staging , the patient was subjected to f-18 fdg pet / ct examination 2 months after the biopsy ( this delay was due to late reporting of the patient to our institute from the peripheral center ) .
the ct scan revealed moderate fdg uptake in the periphery of an ill - defined heterogeneously enhancing soft tissue lesion 2.9  2.2 cm in size involving corpora cavernosa on the left side of the distal penile shaft .
this mass showed slightly thick , peripheral rim enhancement on the contrast - enhanced ct images corresponding to an area of increased f-18 fdg uptake , with an internal homogeneous region of low density , compared to the adjacent normal shaft of the penis , representing residual disease [ figures 1a and 1b ] .
taking into consideration possible microscopic lymph node metastases total penectomy and bilateral inguinal lymphadenectomy was planned and the patient was counseled .
however , the patient refused to undergo lymphadenectomy and only total penectomy was done . on follow - up after 8 months , the patient was found to be disease free .
( a ) contrast - enhanced axial ct through the penis demonstrates a low attenuating lesion in the corpora of the penis with peripheral enhancement .
( b ) f18-fdg pet image fused with corresponding ct demonstrates increased fdg uptake in the periphery of an ill - defined lesion within the corpora of the penis .
( c ) histopathological examination shows tumor composed of spindle cells with hyperchromatic nuclei , inconspicuous nucleoli with frequent mitoses ( d ) histopathological examination shows positivity for smooth muscle antigen
penile cancer is a rare neoplasm and accounts for approximately 0.4% of all male malignancies .
the most common primary malignant neoplasm of the penis is squamous cell carcinoma , constituting more than 95% of cases , followed by metastatic neoplasms of the prostate , bladder , rectum , kidney , and testis , as well as those spreading by direct extension from the adjacent structures .
it accounts for 1020 % of all malignancies in males in asia , africa , south america , and it has a prevalence of only 1% in western countries .
predisposing factors are phimosis , cigarette smoking , and human papilloma virus ( hpv ) infection
. other tumors of the genitourinary tract include sarcoma , melanoma , basal cell carcinoma , and lymphoma .
sarcomas are uncommon penile neoplasms , which include epithelioid sarcoma , kaposi sarcoma , leiomyosarcoma , and rhabdomyosarcoma .
in general , very little literature exists that discusses the management of penile leimyosarcoma , due to the rarity of disease .
role of routine lymphadenectomy is controversial as few authors have suggested that regional lymph node dissection is usually not indicated , since nodal metastases are uncommon . in our case
lymphadenectomy was planned ; however , patient refused to undergo lymphadenectomy and was managed only with total penectomy .
the ct findings of penile leiomyosarcoma are also rarely reported in literature in which the tumor may appear as a mass showing a relatively thick peripheral rim enhancement with internal regions of homogeneous low density , compared to the adjacent normal shaft of the penis , ( similar to findings in our case ) or as a soft tissue mass .
fdg uptake has been described in penile squamous cell carcinomas and f-18 fdg pet / ct has been shown to be useful in detection of lymph nodal and distant metastases in penile carcinoma .
f-18 fdg uptake has also been described in leiomyosarcomas and tumoral f-18 fdg uptake correlates well with the grade of the tumor in case of leiomyosarcomas .
f-18 fdg pet / ct plays an important role in diagnosis , staging , treatment response monitoring , and follow - up in patients with sarcomas .
this is the first case demonstrating f-18 fdg pet / ct findings in a case of penile leimyosarcoma .
 penile cancer is a rare entity accounting for only 0.4% all male malignancies . 
 penile leiomyosarcomas are even rarer with only around 35 cases reported in literature . 
 we report a rare case of penile leiomyosarcoma illustrating f-18 fluorodeoxy glucose ( fdg ) positron emission tomography / computed tomography ( pet / ct ) features and histopathology correlation . 
INTRODUCTION
CASE REPORT
DISCUSSION