Testicular carcinoid tumour associated with carcinoid syndrome

Clinical History

A 49-year-old man presented with h/o breathlessness and bilateral lower limb swelling for the past 2 months. On examination, an early ejection systolic murmur was heard in pulmonary area and diastolic murmur in the tricuspid area. The right testis had been enlarged for 10 years, with recent increase in size.

Imaging Findings

USG showed a grossly enlarged right testis measuring 5x4.8 cm with diffuse heteroechogenity. Few hypoechoic areas suggestive of necrosis and dense calcific foci were present (Fig. 1). On Doppler there was increased vascularity (Fig. 2).
CT showed a large right testicular mass with increased vascularity, heterogeneous contrast enhancement, necrotic areas and few calcific foci (Fig. 4a, b). The other abdominal organs were normal. Cardiomegaly with predominantly right chambers enlargement was present (Fig. 3). Tracheobronchial tree (Fig. 5) and lungs were normal. Echocardiography showed severe tricuspid and pulmonary regurgitation and stenosis.
Laboratory investigations: - S. b-hCG: 0.1 mIU/ml (up to 5.3 mIU/ml), S. AFP : 4ng/ml (0-7 ng/ml), S.LDH : 191 IU/L (240-480 IU/L), 24 hr urine 5-HIAA: 29mg (2 to 6 mg/24 hr).
Right orchidectomy was performed. It showed a solid mass, tan to white in colour with necrotic areas (Fig. 6). Histopathology confirmed carcinoid tumour.

Discussion

Carcinoid tumour arises from neuroendocrine cells that release serotonin and other vasoactive substances. Carcinoid syndrome results when these substances are in systemic circulation. The manifestations include episodic flushing, wheezing, diarrhoea, and eventual right-side valvular heart disease. Common sites for carcinoid tumours are appendix/ileocaecal region (84%), lung (15%), liver, or genitourinary tract. Carcinoid tumour of the testis is exceedingly rare (<1%) of all testicular neoplasms. [1-5]

This tumour presents as a painless testicular enlargement or a discrete testicular mass. Rarely (1- 3%) these tumours are complicated by carcinoid syndrome. Testicular carcinoid tumours do not show predilection for age; cases have been reported from 10-83 years of age. [3]
Testicular carcinoid tumours have been divided into 3 subgroups: primary testicular carcinoid, carcinoid associated with teratoma, and carcinoid metastasis to the testis. [3]

Carcinoid syndrome is also more common in a carcinoid tumour with metastasis (>50%) than carcinoid tumours without metastases (5.6%) and with larger tumours [1, 2]. Primary testicular carcinoid tumours are treated as benign lesions, while metastatic carcinoid tumours have a poor prognosis regardless of the primary site [5].

Sonographic features of testicular carcinoid tumours are solid, well-defined, hypoechoic intratesticular masses containing dense calcification [1, 2, 3, 5]. On Doppler ultrasound of our case, increased vascularity was also noted, and this finding may also be shown in seminoma or lymphoma [1].

Radical orchiectomy remains the main treatment for carcinoid testis tumour. Grossly, the tumour presents as a solid mass, tan to white in colour. During operation, there was fluctuation in our patient’s BP and heart rate, which is seen in carcinoid tumours.

Immunohistochemical study shows that tumour cells are diffusely reactive to antibodies to
keratins AE1 and AE3, chromogranin-A, neuron-specific enolase (NSE), and synaptophysin [2]. The histogenesis of testicular carcinoid tumour is of germ cell origin [3, 4]. Testicular carcinoid tumours exhibit the presence of 12p isochromosomy, the classic genetic alterations that characterize germ cell tumours [4].

To rule out the possibility of metastasis from an extra-testicular primary carcinoid, chest radiography, CT of chest and abdomen and octreotide scintigraphy are indicated [2].
Metastatic potential exists for these tumours and regular follow-up is indicated. Urine 5-hydroxyindolacetic acid (5-HIAA), review history, and physical examination every 3 months for 1 year and then yearly thereafter is suggested [2].

In conclusion, primary carcinoid of the testis is rare and imaging features are non-specific. The radiologist should be specifically alerted to the possibility when typical symptoms of carcinoid syndrome and right heart valvular disease are present.

Differential Diagnosis List

Final Diagnosis

Primary testicular carcinoid tumour with carcinoid syndrome.

URL:	https://www.eurorad.org/case/11499
DOI:	10.1594/EURORAD/CASE.11499
ISSN:	1563-4086