# Double PitNETs: A Case Report and Literature Review

## TL;DR

Double pituitary neuroendocrine tumors are rare and complex, with varied clinical and diagnostic features that require multidisciplinary understanding.

## Contribution

A comprehensive analysis of 142 cases of double PitNETs reveals updated trends in tumor types and clinical manifestations.

## Key findings

- Double PitNETs often present with hormonal excess symptoms, with acromegaly being the most common clinical feature.
- There is a recent increase in the proportion of endocrine-inactive and gonadotroph tumors among double PitNETs.
- MRI findings show that double PitNETs are frequently detected as single tumors, requiring careful surgical attention to hidden micro-tumors.

## Abstract

Pituitary lesions include tumors, cysts, and inflammation, with a very low incidence of double pituitary neuroendocrine tumors (double PitNETs). Double PitNETs are a challenging condition in clinical practice due to their wide variety of clinical, pathological, and radiological features. We performed a literature review and identified 142 cases of double PitNETs, including the present case, and analyzed the clinical manifestations, pathological findings of each tumor, and radiological features of cases using MRI findings. Despite the infrequency of clinically evident double PitNETs, the number of reported cases is increasing, and the present analyses indicate a recent increase in the proportion of endocrine-inactive cases and gonadotroph tumors. This complicated disease is becoming clearer, and endocrinologists, pituitary neurosurgeons, and pathologists need to understand the unique features of double PitNETs.

Double pituitary neuroendocrine tumors (double PitNETs) are two distinct tumors in the same gland and are infrequent in clinical practice. In typical double PitNETs, an MRI detects two separate tumors that are diagnosed by pathology; they could also appear as a single tumor, and pathology would then identify the two independent tumors. A literature review was conducted, and 142 cases were analyzed to determine the characteristics of double PitNETs. Of these cases, acromegaly (45.5%) was the most common clinical feature, followed by Cushing’s disease (35.1%) and prolactinoma (17.9%), indicating that double PitNETs are usually noticed by hormonal excess symptoms due to at least one functional tumor. The pathological analysis of 284 tumors showed that somatotroph (28.9%) and corticotroph (26.8%) tumors were predominant, with a recent increase in the proportion of gonadotroph tumors. Regarding transcription factors, 51.1% were of GH-PRL-TSH PIT1-lineage, 26.1% ACTH TPIT-lineage, and 17.9% LH-FSH SF1-lineage. The radiological analysis of 82 cases revealed that double tumors (45.1%) and single tumors (47.6%) were comparable, suggesting that double PitNETs are often detected as a single tumor, and attention should be paid to hidden micro-tumors during surgery. Double PitNETs are complicated by a wide variety of clinical, radiological, and pathological findings, but diagnostic and therapeutic approaches are advancing.