Seeding of a Pituitary Adenoma or Atypical Pituitary Carcinoma?

Abstract

Pituitary carcinomas are defined as pituitary tumors with craniospinal and/or systemic metastasis. These are rare and highly aggressive lesions. We present an unusual case of a 52-year-old male who had a pituitary adenoma removed via craniotomy. The tumor recurred three years post-op near the surgical tract, and slowly enlarged before removal two years later. Technically, this lesion was defined as a pituitary carcinoma, even though the histology and clinical course were atypical. There is no standardized grading system for pituitary tumors and ideal criteria should correlate clinically. Treatment for pituitary carcinoma is multimodal and largely empiric. We believe this case illustrates that current definitions of pituitary carcinoma are incomplete.

Aggressive and malignant pituitary tumours: state-of-the-art

“…The tumour recurred 3 years post-operatively near the surgical tract, and slowly enlarged before removal 2 years later. Technically, this lesion could be defined as a pituitary carcinoma; however, the origin of the secondary mass(es) in this case is quite unclear, with similar histology in the second mass compared to that initially removed (Krueger & Seibly 2017). While this patient received CyberKnife therapy for a residual mass following the initial surgery, there is no evidence to support radiation-induced PAs specifically (Minniti et al 2005), and it remains possible that there was iatrogenic seeding along the surgical tract (Taylor et al 1994).…”

“…An unusual case presented by Krueger et al complicates the matter even further (Krueger & Seibly 2017). They reported a 52-year-old man who had a pituitary adenoma removed via a craniotomy.…”

“…Tanaka et al described a case of a patient who developed multiple supra-tentorial, cerebellar and cervical spine dural metastases 13 years after initial surgical operation for a pituitary adenoma (Tanaka et al 2013). Thus, even apparently benign adenomas require long-term follow-up (Krueger & Seibly 2017).…”

Disseminated leptomeningeal spread of sinonasal adenocarcinoma of the intestinal type

“…4,5 Leptomeningeal dissemination of sITAC has been previously described at the time of diagnosis in a single case report by Bacaicoa Saralegui et al 6 The stepwise pathway of invasion through the cribriform plate into the subarachnoid space appears clear in our case report and is supported by histological and radiological findings. Facilitation of cancerous cells spreading into the CSF space due to surgery has been proposed in pituitary carcinoma, and may well represent the modality of dissemination in this case also, 7 an important difference from the case published by Bacaicoa Saralegui et al…”

Delayed Craniospinal Metastasis of Aggressive Nonfunctioning Pituitary Adenomas as Pituitary Carcinomas

“…Reports of pituitary adenoma recurrence along the surgical tract highlights the possibility of surgical seeding. [13][14][15] Exposure of the third ventricle may provide an opportunity for amenable tumors to seed caudally along the spinal fluid pathways, a possibility others have considered. [16][17][18] Our patients had undergone aggressive, but necessary, subtotal resections via a transcranial approach which could have increased the tumors access to the subarachnoid space by removing the majority of the arachnoid attached to the tumor in the suprasellar cistern.…”