Carney's triad

[Translational research and diagnosis in GIST]

Gastrointestinal stromal tumors (GIST) are the most common mesenchymal tumors in the digestive tract. In up to 90% of cases, they are characterized by activating mutations in the KIT or the PDGFRA gene. GIST represent a paradigm for successful targeted treatment with tyrosine kinase inhibitors (TKI). Since the approval of the TKI imatinib in 2002 the survival of patients with metastatic GIST has tripled. The next logical step was the concept of using imatinib in an adjuvant approach, which was recently shown to increase overall survival significantly. In both settings, the mutational status has high predictive implications. In detail, GIST with KIT exon 11 mutations show the best response rates with partial remission rates of up to 80%. In KIT exon 9 mutations, a doubled daily dose of 800 mg imatinib is now standard. The PDGFRA exon 18 mutation D842V has been shown to lead to primary resistance. The treatment strategy in GIST is driven by their molecular characterisation. Further research has increased our knowledge on resistance mechanisms in solid tumors against TKI. The number of patients with secondary resistance due to acquired KIT mutations is increasing with treatment duration. Strategies to address this situation are the introduction of novel pathway inhibitors targeting different levels of signal transduction pathways, such as the mTOR/Akt pathway, the RAS/RAF pathway, histone deacetylation, among others. Among the GIST without mutations in the common hot spot regions of KIT and PDGFRA, the so-called wildtype GIST, further genomic subgroups have been identified. One such subgroup carries inactivating germline mutations in the genes encoding succinate dehydrogenase B, C, or D. They are associated with the occurrence of paragangliomas, so-called Carney-Stratakis syndrome. Most frequently, these GIST are located in the stomach, showing an epithelioid phenotype and a multinodular growth pattern. They preferentially occur in young females and often show lymph node metastases, the latter being very unusual in sporadic GIST. In sporadic Carney's triad additional pulmonary chondromas are observed and there are no SDH mutations. Another small subgroup of sporadic GIST present with BRAF mutations as an alternative genomic event. Finally, very rare kindreds with germline mutations in either KIT or PDGFRA have been described who develop multiple GIST and depending on the mutational subtype mastocytosis, hyperpigmentation and/or dysphagia. In summary, the molecular characterisation of GIST has revolutionized their treatment due to increasing knowledge about the high relevance of predictive molecular typing in solid tumors.

Pediatric extraadrenal paraganglioma

BACKGROUND

Pediatric paraganglioma is rare and extraadrenal paraganglioma has not been characterized in children.

METHODS

The authors reviewed the medical records and pathology samples of children with extraadrenal paraganglioma treated at our institution between December 1978 and September 2000. Clinical presentation, treatment, and outcome were evaluated.

RESULTS

Eight patients (median age, 11.4 years) were identified, 4 were boys and none had a family history of paraganglioma or associated syndromes. Primary tumors arose in the retroperitoneum (n = 3), carotid body (n = 2), jugulotympanic ganglion (n = 1), cervical-paraspinal region (n = 1), and lung (n = 1). Extraadrenal paraganglioma had not been suspected at presentation in any patient. Of 5 patients who underwent gross total resection at the time of diagnosis, 4 remain disease free, 1 had microscopic residual tumor and died of disease. Three patients had initially unresectable disease, 2 are disease free after neoadjuvant therapy and delayed surgery, and 1 has persistent disease after tumor embolization and radiotherapy.

CONCLUSIONS

Pediatric extraadrenal paraganglioma occurs most commonly in the retroperitoneum and head and neck, and the diagnosis usually is not suspected at the time of presentation. Surgery is the mainstay of treatment, and outcome is good after gross total resection. Neoadjuvant therapy can facilitate complete resection of initially unresectable tumors.

Gastric stromal sarcoma, pulmonary chondroma, and extra-adrenal paraganglioma (Carney Triad): natural history, adrenocortical component, and possible familial occurrence

OBJECTIVE

To investigate the natural history of the triad of gastric stromal sarcoma, pulmonary chondroma, and extra-adrenal paraganglioma, a rare syndrome of unknown cause primarily affecting young women.

METHODS

Mayo Clinic records, the world literature, and the author's files were searched for patients with all or 2 of the 3 tumors.

RESULTS

Seventy-nine patients, 67 women and 12 men, were identified, 17 (22%) with the 3 tumors and 62 (78%) with 2 tumors. Forty-two (53%) had gastric and pulmonary tumors, the most common combination. The longest interval between detection of the first and second components was 26 years (mean, 8.4 years; median, 6 years). Follow-up ranged from 1 year to 49 years (mean, 20.6 years; median, 20 years). Sixty-four patients (81%) were alive, 19 (24%) apparently free of disease and 45 (57%) with residual or metastatic tumors. Thirty-two patients (41%) had had 1 or more local recurrences of the gastric sarcoma; the longest interval to first recurrence was 36 years. Twenty-one survivors (27%) had hepatic metastatic gastric sarcoma with follow-up of 1 year to 25 years (mean, 9.3 years; median, 7 years). Fifteen patients (19%) were dead, 10 (13%) of whom died of the disorder. Ten patients (13%) had nonfunctioning adrenocortical tumors. Two patients each had a sibling with 1 component of the triad.

CONCLUSIONS

The triad is a chronic, persistent, and indolent disease. Benign adrenocortical tumors are a component of the condition. The disorder may be familial.