Carney triad (ECR 2016 Case of the Day)

Clinical History

A 24-year-old woman was referred for CT evaluation of an epigastric mass detected at sonography performed for vague epigastric discomfort. She was otherwise asymptomatic. Laboratory studies were unremarkable.

Imaging Findings

CT scan demonstrated an exophytic mass from the medial aspect of the gastric fundus (Fig. 1), consistent with gastrointestinal stromal tumour (GIST), which was resected. Chest staging CT showed bilateral calcified lung nodules (Fig. 2) suggesting pulmonary chondromas and a nodule in the aortopulmonary window with intense contrast enhancement (Fig. 3). Follow-up CT scan 6 years later (Fig. 4) shows further calcification and enlargement of prior lung lesions, as well as appearance of a new nodule in the left lower lobe (arrow). These lesions should not be confused with calcified metastases. Octreotide scan (Fig. 5) was performed for suspicion of aortopulmonary paraganglioma, demonstrating intense uptake. Paraganglioma was confirmed by endobronchial ultrasound- guided (EBUS) guided fine needle aspiration biopsy.

Discussion

BACKGROUND
The Carney triad, first described by JA Carney in 1977 [1], is a rare syndrome defined by concomitant or consecutive occurrence of three tumors: gastric GIST, pulmonary chondromas and extra-adrenal paraganglioma.
It typically affects young people and is more frequent in females [1- 4]. It is a sporadic condition of unknown aetiology. Recent papers have suggested a possible genetic relation with succinate dehydrogenase (SDH) mutations in some cases [3-5].
CLINICAL PRESENTATION
In most cases the triad is incomplete at the time of diagnosis, with only 2 of the 3 tumors [3]. In our case, all 3 tumors were present at the time of diagnosis. A fourth component, adrenocortical adenoma, has been suggested [6].
IMAGING PERSPECTIVE
Unusual features in a GIST should alert radiologists of an SDH-deficient GIST: young age, female sex, gastric location, multifocality, metastasis to the lymph nodes, prolonged survival and association with findings of the Carney triad or Carney-Stratakis syndrome (a familial syndrome characterized by GIST and paragangliomas) [4, 5, 7]. Diagnosis of an SDH-deficient GIST is important since they usually demonstrate resistance to imatinib [4, 5, 7].
Pulmonary chondromas are benign lesions. They may be multiple and bilateral and tend to grow and calcify progressively over the years [3]. These lesions should not be confused with calcified metastases.
The paraganglioma is the least frequent of the 3 tumours, and may appear anywhere in the paraganglionic system [6]. Exclusion of a catecholamine-secreting paraganglioma is a requisite before surgery or biopsy [3]. Paragangliomas should not me mistaken for lymphadenopathy, Castleman’s disease or mediastinal haemangioma.
TAKE HOME MESSAGE
In conclusion, recognition of the Carney triad is important in young patients presenting with gastric GIST, calcified lung nodules or paraganglioma. GISTs may present atypical characteristics and may display resistance to imatinib. Lung chondromas should not be mistaken for metastases. Functioning paraganglioma must be excluded before intervention.

Differential Diagnosis List

Final Diagnosis

Carney triad

URL:	https://www.eurorad.org/case/13756
DOI:	10.1594/EURORAD/CASE.13756
ISSN:	1563-4086