Description
Carney Triad is a rare, non-heritable syndrome typically presenting in young females. It comprises of gastrointestinal stromal tumours (GISTs), pulmonary chondromas, and paragangliomas. Although the presence of any two can be sufficient for diagnosis, complete triads are found in only a third of the patients.
Pathogenesis
The pathogenesis of Carney Triad is not well understood due to its sporadic nature and the absence of a recognised associated genetic mutation. It is believed that epigenetic factors may play a significant role in its development.
Subtypes
Carney Triad does not have any recognised subtypes.
Epidemiology, Risk Factors & Associations
- Predominantly affects females (almost 90% of cases).
- Most cases are diagnosed in the second or third decade of life.
- No known geographical or racial predilection.
Clinical Features
- Symptoms are non-specific and relate to the tumour’s size and location.
- Common presentations include abdominal pain, anaemia, and gastrointestinal bleeding (due to GISTs).
Complications
- Potential for tumour rupture and haemorrhage.
- Risk of malignancy, especially associated with GISTs.
Pathological Features
Histopathology
- Macroscopic: Tumours can vary in size, with GISTs often appearing as submucosal masses in the stomach.
- Microscopic: GISTs show spindle cell morphology, while chondromas display hyaline cartilage, and paragangliomas exhibit the characteristic ‘Zellballen’ pattern.
Serology
- Non-specific.
Biochemistry
- Normal in most cases, unless there is endocrine activity associated with the paragangliomas.
Radiological Features
General Features
- GISTs typically present as a well-defined soft tissue mass arising from the stomach wall.
- Pulmonary chondromas often present as multiple well-defined nodules scattered throughout the lungs.
- Paragangliomas are usually seen as well-defined, enhancing soft tissue masses.
CT
- Non-contrast: May show calcification within the tumours.
- Contrast-enhanced: Tumours usually enhance post-contrast, particularly GISTs and paragangliomas.
MRI
- T1: Tumours are typically isointense to muscle.
- T2: Tumours can be hyperintense.
- T1 C+: Post-contrast, tumours usually show enhancement.
- DWI/ADC: Diffusion restriction may be seen in malignant GISTs and paragangliomas.
PET FDG
- Can show increased uptake in malignant GISTs and paragangliomas.
Grading and Staging
There is no recognised grading or staging system for Carney Triad as a whole. Individual tumour types within the triad, especially GISTs, are graded and staged according to their specific criteria.
Diagnosis
- Diagnosis is largely clinical, often requiring a combination of histological and imaging findings. It’s made when at least two of the three tumour types are present.
Differential Diagnosis
- Carney-Stratakis Syndrome: Similar to Carney Triad, but with the presence of SDH gene mutations.
- Neurofibromatosis Type 1: Can present with similar tumours but also has distinctive features like café-au-lait spots and neurofibromas.
- Other causes of pulmonary nodules or abdominal masses.
Management
- Given the risk of malignancy, particularly with GISTs, surgical resection is often recommended when feasible.
- Lifelong surveillance is needed due to the risk of recurrent or new tumours.