|LETTER TO EDITOR
|Year : 2020 | Volume
| Issue : 1 | Page : 112-114
Molecular functional imaging in an unusual case of penile metastasis
Abhishek Mahajan1, GV Santhosh Kumar1, Tanvi Vaidya1, Anurag Gupta1, Archi Agrawal2, Avanish Saklani3, Reena Engineer4, Vikas Otswal5, Supreeta Arya1
1 Department of Radiology, Tata Memorial Hospital, Tata Memorial Centre, Homi Bhabha National Institute (HBNI), Mumbai, Maharashtra, India
2 Department of Nuclear Medicine and Molecular Imaging, Tata Memorial Hospital, Tata Memorial Centre, Homi Bhabha National Institute (HBNI), Mumbai, Maharashtra, India
3 Department of Surgery, Tata Memorial Hospital, Tata Memorial Centre, Homi Bhabha National Institute (HBNI), Mumbai, Maharashtra, India
4 Department of Radiation Oncology, Tata Memorial Hospital, Tata Memorial Centre, Homi Bhabha National Institute (HBNI), Mumbai, Maharashtra, India
5 Department of Medical Oncology, Tata Memorial Hospital, Tata Memorial Centre, Homi Bhabha National Institute (HBNI), Mumbai, Maharashtra, India
|Date of Submission||09-Sep-2019|
|Date of Acceptance||24-Dec-2019|
|Date of Web Publication||24-Feb-2020|
Department of Radiodiagnosis and Imaging, Tata Memorial Hospital, Dr E Borges Road, Parel, Mumbai - 400 012, Maharashtra
Source of Support: None, Conflict of Interest: None
|How to cite this article:|
Mahajan A, Santhosh Kumar G V, Vaidya T, Gupta A, Agrawal A, Saklani A, Engineer R, Otswal V, Arya S. Molecular functional imaging in an unusual case of penile metastasis. Cancer Res Stat Treat 2020;3:112-4
|How to cite this URL:|
Mahajan A, Santhosh Kumar G V, Vaidya T, Gupta A, Agrawal A, Saklani A, Engineer R, Otswal V, Arya S. Molecular functional imaging in an unusual case of penile metastasis. Cancer Res Stat Treat [serial online] 2020 [cited 2020 Apr 10];3:112-4. Available from: http://www.crstonline.com/text.asp?2020/3/1/112/279119
Carcinoma rectum has a favorable prognosis and good survival rate compared to other common cancers such as breast and lung. However, the undifferentiated histological type of rectal cancer is known for early and disseminated metastasis which significantly lowers the survival rates. Penile metastasis is a rare clinical entity even with the high vascular and lymphatic network in the penis. Most of the reported penile metastases are from the pelvic and genitourinary malignancies including the rectum. We present the clinical and imaging features of a case of metastatic deposits to the penis in a patient with carcinoma rectum who presented with an ulcerative growth of the penis.
A 63-year-old male presented with pain and bleeding during defecation for 1 month. Local examination revealed a polypoidal growth of the rectum extending into the perianal region. After initial blood investigations, contrast-enhanced computed tomography (CT) scan of the abdomen and pelvis, and magnetic resonance imaging (MRI) of the pelvis, he was diagnosed with carcinoma of the rectum and was planned for neoadjuvant chemotherapy. In the meantime, the patient presented with an ulcerative growth over the glans of the penis. The patient was initially suspected to have a second primary of the penis; another differential was carcinoma prostate with rectal and penis involvement. The patient was referred to multiple disease management groups for disease assessment.
MRI of the rectum with penis was requested to evaluate the local disease. The MRI showed a symmetrical mural thickening of the rectum and the anal canal with suspicious prostate involvement [Figure 1]. Few soft-tissue nodules were noted over the glans and corpora of the penis, showing similar signal intensity to that of the rectal thickening [Figure 2].
|Figure 1: (a-c) T2-weighted images in sagittal, oblique axial, and oblique coronal planes, revealed T2-weighted intermediate signal intensity wall thickening involving the rectum and anal canal (arrows)|
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|Figure 2: Dedicated magnetic resonance imaging penis after intracorporeal injection of papaverine was performed. Coronal and sagittal T2-weighted images (a and b) showing T2 intermediate deposits (arrows) in corpora cavernosa of the penis|
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The histologies of the rectal biopsy and the penile lesion were both adenocarcinoma, thus proving it to be a carcinoma rectum with penile metastasis. Bulk of the disease was involving the rectum with mild infiltration of the prostate. Hence, the primary site was thought to be rectum which was confirmed on histology. Prostate-specific antigen levels were within normal limits. The patient underwent positron emission tomography-CT (PET-CT) with contrast for distant metastatic evaluation. The PET-CT revealed increased metabolic activity of the rectal tumoral thickening and the three penile metastatic deposits [Figure 3]. No other evidence of distant metastases was noted.
|Figure 3: (a-c) (Axial, sagittal, and coronal images): Positron emission tomography/contrast-enhanced computed tomography images showing increased metabolic activity of the rectal tumoral thickening (arrowhead) and the three penile metastatic deposits (arrows). No other evidence of distant metastasis was noted|
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The patient received regional radiotherapy (external beam radiotherapy) 25 Gy in 5 fractions to the gross tumor volume followed by four cycles of capecitabine and oxaliplatin chemotherapy regimen. The response assessment MRI scan showed a significant favorable response in terms of reduction in the size of primary as well as metastatic penile deposits [Figure 4]. The patient was planned for abdominoperineal resection of the rectal tumor and total penectomy for the metastatic deposits with curative intent.
|Figure 4: (a and b) Posttherapy response assessment magnetic resonance imaging (sagittal and axial images) showing a significant favorable response in terms of reduction in the size of primary rectal disease (arrowhead) as well as metastatic penile deposits (arrow)|
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This is a unique case of isolated penile metastasis with pre- and post-therapy morphological and functional imaging that showed a good response to concurrent chemoradiation.
Fewer than 500 cases of secondary penile metastases have been published in the literature; in these, pelvic organ malignancies were noted as primary malignancy in nearly 80% of cases. Of these, rectal primary was seen in 12.2% of cases, the third most common after urinary bladder carcinoma and carcinoma prostate. In India, one case has been reported by Murhekar et al.
The common presenting features of penile metastasis are priapism, pain, dysuria, urinary retention, and palpable nodule., This is distinct from the primary neoplasm of penis which presents as a growth over the glans of the penis. Various hypotheses about the possible route of metastasis to the penis have been proposed. The possible routes are direct extension, retrograde venous or lymphatic route, arterial embolization, and contamination.,, Corpora cavernosa is more commonly involved than corpora spongiosa.
Imaging features of the penile metastasis include soft-tissue deposits of similar imaging characteristics as the primary tumor. In the early stages, primary penile lesions tend to be superficial, most of them along the glans while metastases tend to be deeper and multifocal.
Ultrasound and CT scan are readily available imaging modalities, but the sensitivity is limited. MRI is a useful and sensitive modality in detecting early deposits. On MRI, the tumor shows hypointensity on T1-weighted images, with intermediate signal intensity in a background of high-signal intensity of corpora cavernosa on T2-weighted images PET-CT shows increased metabolic activity of the metastatic deposits. The final confirmation of the diagnosis needs biopsy and histological examination.
Although the management of these patients is mainly palliative, as most of the patients have distant metastasis, this patient had oligometastasis limited to penis. The patient also had good response to concurrent chemoradiation, opening the path to radical surgery with an intent to cure. In the meantime, the patient was explained about guarded prognosis., This treatment approach is supported by the evidence of improved survival rate after excision of solitary liver/lung metastasis in case of carcinoma rectum.
This is a unique case of isolated penile metastasis that showed good response to concurrent chemoradiation. Although the management of these patients is mainly palliative, as most of the patients have distant metastasis, this patient had metastasis limited to penis and radical surgical treatment can be offered to such patients.
Declaration of patient consent
The authors certify that they have obtained all appropriate patient consent forms. In the form, the patient has given his consent for his images and other clinical information to be reported in the journal. The patient understands that his name and initials will not be published, and due efforts will be made to conceal his identity, but anonymity cannot be guaranteed.
Financial support and sponsorship
Conflicts of interest
There are no conflicts of interest.
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