Signet ring cell adenocarcinoma of the oropharynx: presentation of a rare case and review of the literature.

Intracellular mucin-producing adenocarcinomas, so called signet ring cell adenocarcinomas (SRCAs), are most commonly found in the stomach or lower GI-tract. They occur far less frequently at other locations such as prostate, pancreas, mammarian gland or within the oropharyngeal cavity. We present the case of a patient who suffered from indolent cervical nodular tumour. Biopsy and histopathological workup showed parts of a poorly differentiated SRCA with p53 overexpression and mutations. Immunostaining gave no further hints for the origin of the malignancy. Thorough staging revealed an extended tumour of the oropharynx as primary origin. The definitive surgical therapy consisted of a transoral tumour resection with CO(2)-laser and bilateral neck dissection. Final classification was pN2c cM0 G3 R0 L1 V0. Adjuvant fractioned radiotherapy with 66 Gy was applied because of bilateral lymph node metastases and extracapsular spread. So far only few cases of oropharyngeal SRCAs have been published. These tumours turned out to be either metastases from gastric or lower gastrointestinal primaries, or had the small salivary glands as origin. In all published cases, as well as in our case, radical surgical resection was the first step of a curative therapy trial. Adjuvant targeted therapy with drugs like, e.g. herceptin or imatinib was not possible because of genetic and immunhistochemical findings. Because of the small numbers of published cases, an evaluation long-term outcomes and significance of different adjuvant therapy regimes is barely possible at this time.