Extragonadal germ cell tumours (EGCT) represent 2–5% of all germ cell tumours.1
Primary chriocarcinoma is one of the non-seminomatous EGCT that occur mostly in young men. An international analysis of 635 cases of EGCT of the mediastinum and retroperitoneum has shown ages ranging from 14 to 79 with a median age of 30 years.2
Primary choriocarcinoma is an exceedingly rare and aggressive tumour with much worse prognosis than other histologic subtypes owing to the haematogeneous dissemination at the time of diagnosis.
Most cases arise in the midline structures such as the pineal gland, mediastinum and retroperitoneum in keeping with the theory of mismigration of primordial germ cells along the urogenital ridge during embryogenesis. However cases with involvement of other visceral organs such as the lungs, brain, stomach, small bowel, kidneys and adrenals have been reported.3
Primary pulmonary choriocarcinoma in male is very rare with 14 cases so far reported.4,5
The origin of EGCT especially primary choriocarcinoma has been a topic of controversy and debate. One hypothesis is the reverse migration of occult carcinoma in situ in the gonad with subsequent spontaneous necrosis of the primary with formation of a scar tissue thus the ‘burnt out phenomenon’. However several authors have challenged this concept. Serial sectioning of the testes at autopsy failed to reveal a primary lesion or scar indicative of the burn out tumour.6,7
In addition some authors explain that the presence of scars may be merely the result of trauma and the small teratomas may be secondary to hormonal stimulation from the choriocarcinoma and as such it does not establish the gonad as the primary site of the neoplasm.8,9
Review of the literature support that EGCT represent malignant transformation of local primordial germ cells without a gonadal focus and a routine bilateral testicular biopsy is not recommended.6,9,10
Clinical presentation depends on the location and size of tumour. In a recent meta-analysis representing the largest published series of EGCT with 635 patients, those with mediastinal tumour initially presented with dyspnea, cough and chest pain followed by fever weight loss, superior vena cava syndrome, fatigue and weakness.2
Gynaecomastia has been associated with several conditions both physiologic and pathologic. It can be a result of primary or secondary gonadal failure, liver disease, hyperthyroidism, renal disease and haemodyalysis, testicular and adrenal neoplasms, ectopic production of β HCG by lung, kidney and liver cancer.11
Numerous drugs such as androgens and anabolic steroids, H2 blockers, cardiovascular drugs, psychoactive agents, antibiotics and antifungals, alkylating agents, anticonvulsants, alcohol, marijuana, heroin and amphetamine abuse has also been linked to the development of gynaecomastia.11
The presence of gynaecomastia in a male patient with bilateral pulmonary nodules however is virtually diagnostic of choriocarcinoma until proven otherwise and as such should prompt the clinician to get a urine pregnancy test there by avoiding delay in diagnosis and treatment.5,8
Definitive diagnosis is made with tissue biopsy.
Standard treatment of primary pulmonary choriocarcinoma is four cycles of cis-platin based chemotherapy followed by radical resection of all residual masses when technically feasible. Salvage chemotherapy is utilised for patients with relapse of the disease. Despite current treatment prognosis remains to be extremely dismal especially for those with pulmonary and other visceral involvement at presentation and treatment resistance.
We recognise the diagnosis of primary pulmonary choriocarcinoma should be made after careful consideration of many of the existing hypothesis. To this effect we have considered the following findings before making the diagnosis. On reviewing the literature, multiple pulmonary nodules have been reported as a radiological manifestation of primary pulmonary choriocarcinoma.5
The absence of testicular mass in the phase of wide spread metastatic disease is very uncommon.12
Even though we do not agree with the concept of ‘burnt out testicular focus’ current high resolution ultrasonography of the testes has proven to detect non-palpable intratesticular masses and calcifications that correlate very well with pathological characteristics of burnt out tumours.13
This has been confirmed in several retrospective reviews of patients with clinically normal testes and a diagnosis of presumed EGCT that underwent ultrasonography.12–15
Our patient had a normal testicular ultrasound as well as normal CT scan of the retroperitoneum and pelvis.
Testicular choriocarcinoma has relatively a better response to the current standard cis-platin based chemotherapy. In the case of our patient, he presented with advanced disease with evidence of metastasis to the liver and brain which rendered the tumour to be resistant to treatment.
- Primary pulmonary choriocarcinoma in the male is an exceedingly rare and aggressive non-seminomatous EGCT.
- The presence of gynaecomastia in a male patient with bilateral pulmonary nodules should raise a clinical suspicion of primary choriocarcinoma there by prompting the clinician to perform a thorough testicular examination along with high resolution ultrasonography of the testes to rule out a testicular primary.
- Urine or serum β HCG is a quick and affordable test that will help make a rapid diagnosis, there by preventing delay in diagnosis and potentially curative treatment.