Mixed adenoneuroendocrine carcinoma: case report and review of literature

Mixed adenoneuroendocrine carcinoma (MANEC) is a rare malignant neoplasm of a complex pathomorphological pattern combining the features of adenocarcinoma with a neuroendocrine component. According to the new classification of the World Health Organization (WHO) from 2010, the nomenclature of neuroendocrine neoplasms (NEN) was changed using this name for the entire group of neoplasms. The name ‘neuroendocrine tumours’ covers highly diversified neoplasms, determined in the pathomorphological comparison as G1 (NET G1) or G2 (NET G2). In addition, neuroendocrine carcinomas (NEC) and mixed adenoneuroendocrine carcinomas (MANEC) are differentiated. In a search of the the PubMed database, approximately 50 reports about this carcinoma were found, mainly with the location in the stomach, lymph nodes, intestines, liver, peritoneum, gallbladder, pancreas, oesophagus. We have not found a description of the metastatic lesions typical of MANEC in the meninges, brainstem, and lungs. We present the case of a 63-year-old patient who was admitted to the Department of Neurology due to increased dizzi­ness with accompanying diplopia, headache, nausea, and numbness of the hands. These symptoms appeared one day prior to admission, with intensification at night. The patient was initially diagnosed at the Department of Laryngology due to deafness of the right ear and deep hearing loss in the left ear four weeks prior to admission to our department. In the neurological examination, the following findings were detected: conscious, anxious, dysarthric speech, insignificant inspiratory dyspnoea, deafness of the right ear, deep hearing loss in the left ear, pharyngeal and palatal reaction, weak tension of the palato-pharyngeal fold, bilateral signs of central damage of the seventh nerve, insignificant deviation of the tongue to the left, muscle tone of the limbs without deficit, insignificantly decreased muscle tone in the left limbs, ataxia in the lower limbs, bilateral plantar reflex. In the admissions ward, CT examination of the head was performed and a hypodense focus in the left cerebral hemisphere, hypodense foci around the frontal horn of the lateral ventricles and small malacia cavities at the level of the subcortical nuclei were detected. A lumbar puncture was performed obtaining fluid with increased cytosis and a decreased glucose level. On the second day of hospitalisation, the general and neurological condition of the patient significantly worsened and a ‘sympathetic storming’ appeared followed by circulatory arrest. The patient was efficiently resuscitated, but then there was another sudden cardiac arrest and despite a long period of CPR, cardiac and respiratory action was not restored. After pathomorphological examination it was established that the whole image corresponded to MANEC located in the stomach, with dissemination mainly to the meninges, brainstem and lungs. In differential diagnosis rare causes of diseases must always be taken into consideration. An additional difficulty in diagnosing MANEC is a difference in the names depending on literature and country of the origin of the article, as well as the lack of Polish equivalents of some names of neoplasms. Only a reliable histopathological analysis is able to detect neoplasms from this group.