Testicular embryonal carcinoma presenting as chest wall subcutaneous mass.

Embryonal carcinoma affects young males in the prime of life with a majority of these tumors already having metastasis at the time of diagnosis. Subcutaneous metastasis from embryonal carcinoma are very rare and often associated with wide spread disease and poor prognosis. We report a case of chest wall subcutaneous metastasis of embryonal carcinoma in a 27 year-old man that was the first presentation of the disease and was diagnosed on fine needle aspiration cytology (FNAC). Subsequent search led to the discovery of the primary in the testis. The cytomorphological features of embryonal carcinoma are quite distinctive and FNAC plays a vital role in early diagnosis. The criteria for diagnosis includes presence of cellular smears exhibiting disperse cells as well as cell aggregates forming microglandular patterns. Cells have large nuclei with prominent nucleoli and pale indistinct often vacuolated cytoplasm. Early diagnosis and treatment with platinum based chemotherapy in conjunction with radiotherapy and surgery have high cure rate.

Introduction

Although pure embryonal carcinoma is a relatively rare neoplasm,[12] it is the most common component in mixed germ cell tumors.[3] Embryonal carcinoma tends to occur at a young age, the average age being 31 years.[1] Many (66%) patients with a tumor composed predominantly of embryonal carcinoma, have metastasis at the time of diagnosis;[4] subcutaneous metastasis of embryonal carcinoma is rare.[5-7]

Here, we report a case of chest wall subcutaneous metastasis of an embryonal carcinoma, emphasizing the role of fine needle aspiration cytology (FNAC) as a modality for early diagnosis and treatment.

Case Report

A 27 year-old man presented with a gradually increasing, subcutaneous swelling in the anterior chest wall, extending up to the axilla. The swelling measured 8×10 cm, was firm in consistency, fixed to the chest wall, and was non tender with prominence of overlying veins.

The patient was subjected to FNAC, which revealed syncytial clusters of anaplastic tumor cells exhibiting pleomorphism and anisonucleosis. Cells had round to irregular, vesicular nuclei and prominent nucleoli [Figure 1]. A diagnosis of a poorly differentiated neoplasm suggestive of embryonal carcinoma, was made. With these cytological findings, the patient was evaluated in detail and a mass was detected in the left testis.

Figure 1

Adenocarcinoma-like cluster of large malignant cells with large nuclei, coarse chromatin, and occasional prominent nucleoli (H and E, ×400)

Ultrasonography (USG) of the whole abdomen showed multiple liver metastasis, spleen metastasis, enlargement of the retroperitoneal and paraortic lymph nodes, and bilateral pleural effusion.

Biopsy of the testicular mass confirmed the cytological diagnosis of an embryonal carcinoma [Figure 2].

Figure 2

Primitive hyperchromatic cells forming sheets and glands (H and E, ×100)

Discussion

Most of the germ cell tumors originate in the gonads. Extragonadal germ cell tumors are also encountered, they commonly arise in the midline of the retroperitoneum or the mediastinum. Primary cutaneous extragonadal germ cell tumors on the other hand are very rare; only two cases have been reported.[6] The diagnosis should be rendered only after extensive search for primary in the gonads, mediastinum and retroperitoneum have failed to yield positive results.

Cutaneous metastasis of a malignant germ cell tumor is again very rare.[57] It may be the first presentation of the primary tumor. Nakahira et al.[5] reported subcutaneous deposits of an embryonal carcinoma. On analysis of their Institute's 30 year data Wesche et al.[7] encountered two cases of cutaneous metastatic deposits of choriocarcinoma in children and adolescents. The subcutaneous chest wall deposit in our case was the initial presentation. FNAC was instrumental in suggesting a diagnosis and the subsequent search led to the discovery of the primary in the testis with dissemination in the abdominal lymph nodes, liver and spleen.

Testicular germ cell tumors are the most commonly occurring neoplasm in young males.[8] Although the overwhelming majority are malignant, they are curable.[9] The high sensitivity of germ cell tumor to platinum based chemotherapy, together with radiation and surgical measures leads to high cure rate of ≥99% in the early stages, 90%, 75-80% and 50% in advanced disease with ‘good’ ‘intermediate’ and ‘poor’ prognostic criteria (International Germ Cell Cancer Consensus Group IGCCCG classification) respectively.[8]

An embryonal carcinoma is an aggressive tumor due to its tendency to early hematogenous spread emphasizing the need for early detection and treatment. Cytomorphological features such as syncytial aggregates of round to irregular nuclei with prominent nucleoli and scant cytoplasm are quite distinctive.

Fine needle aspiration is an excellent cytological method for the early diagnosis of embryonal carcinoma, based on which the patient can be spared the morbidity and expense of extensive surgical procedures. Moreover, early treatment with the administration of chemotherapy can produce high cure rates, thereby saving the lives of patients