Endocrine Abstracts

We present the case of a 67-year-old man who presented to the outpatient clinic for endocrinological evaluation after partial resection of an atypical pituitary adenoma (APA). Pathohistological assessment of two independent and experienced neuropathologists resulted in a diagnosis of APA with unusually high proliferation indices (Ki67 10–20%/p53 30%) and immunoreactivity for LH, FSH and the alpha-subunit. Clinical examination as well as laboratory testing revealed no significant pathologies, particularly with regard to the pituitary function. This was also true at the follow-up examination 6 month later, after the patient received adjuvant radiotherapy. Another 8 month later the patient presented in a markedly deteriorated state with fatigue and chronic pain syndrome due to multiple vertebral body fractures. Medical workup revealed the diagnosis of a stage III (International Staging System) IgG-kappa type multiple myeloma. With knowledge of the underlying disease the neuropathological examinations were repeated and immunohistochemical staining with antibodies to CD138, CD38 and kappa light chains confirmed pituitary manifestation of the multiple myeloma, although positive staining for LH, FSH and the alpha-subunit was present. On the basis of these findings 138 classical histological specimens of multiple myelomas were examined regarding to gonadotropin and alpha-subunit expression: 2 and 3 tumors expressed LH and FSH, respectively, and nuclear and cytoplasmatic staining of the alpha-subunit was present in a multitude of cases. Most likely, unspecific binding of the used antibodies caused the positive staining. However, in the presented case, this phenomenon supported the initial diagnosis auf APA. This case illustrates that extraosseous manifestation of a multiple myeloma should be considered in cases of APA with high proliferation indices.