Familial Cushing's syndrome

A large family with Carney complex caused by the S147G PRKAR1A mutation shows a unique spectrum of disease including adrenocortical cancer

CONTEXT

Most tumors in Carney complex (CNC) are benign, including primary pigmented nodular adrenocortical disease (PPNAD), the main endocrine tumor in CNC. Adrenocortical cancer (AC) has never been observed in the syndrome. Herein, we describe a large Azorean family with CNC caused by a point mutation in the PRKAR1A gene coding for type 1-α (RIα) regulatory subunit of the cAMP-dependent protein kinase A, in which the index patient presented with AC.

OBJECTIVE

We studied the genotype-phenotype correlation in CNC.

DESIGN AND SETTING

We reported on case series and in vitro testing of the PRKAR1A mutation in a tertiary care referral center.

PATIENTS

Twenty-two members of a family were investigated for Cushing syndrome and other CNC components; their DNA was sequenced for PRKAR1A mutations.

RESULTS

Cushing syndrome due to PPNAD occurred in four patients, including the proposita who presented with AC and three who had Cushing syndrome and/or PPNAD. Lentigines were found in six additional patients who did not have PPNAD. A base substitution (c.439A>G/p.S147G) in PRKAR1A was identified in the proposita, in the three others with PPNAD, in the proposita's twin daughters who had lentigines but no evidence of hypercortisolism, and in five other family members, including one without lentigines or evidence of hypercortisolism. Unlike in other RIα defects, loss of heterozygosity was not observed in AC. The S147G mutation was compared to other expressed PRKAR1A mutations; it led to decreased cAMP and catalytic subunit binding by RIα and increased protein kinase A activity in vitro.

CONCLUSIONS

In a large family with CNC, one amino acid substitution caused a spectrum of adrenal disease that ranged from lack of manifestations to cancer. PPNAD and AC were the only manifestations of CNC in these patients, in addition to lentigines. These data have implications for counseling patients with CNC and are significant in documenting the first case of AC in the context of PPNAD.

Primary pigmented nodular adrenocortical disease and Cushing's syndrome

Primary pigmented nodular adrenocortical disease (PPNAD) is a form of bilateral adrenocortical hyperplasia that is often associated with corticotrophin (ACTH)-independent Cushing's syndrome (CS) and is characterized by small to normal-sized adrenal glands containing multiple small cortical pigmented nodules (1,2). PPNAD may occur in an isolated form or associated with a multiple neoplasia syndrome, the complex of spotty skin pigmentation, myxomas, and endocrine overactivity, or Carney complex, in which Cushing's syndrome is the most common endocrine manifestation (3). Molecular studies have led to the identification of several genes, defects in which may predispose PPNAD formation; all of these molecules play important role for the cAMP signaling pathway. This review intends to present the most recent knowledge of the pathology and molecular genetics of the benign bilateral adrenocortical lesions, as well as to discuss the modern tools for diagnostics and treatment of this condition.

Primary pigmented nodular adrenocortical dysplasia

A 29-year-old female patient presented clinical features of Cushing's syndrome. Biochemical tests suggested the presence of an autonomously functioning adrenocortical neoplasm. However, the adrenal glands were normal on MRI. Diagnostic adrenalectomy revealed a slightly enlarged organ studded externally and on multiple cut surfaces by small yellow and brown nodules. Microscopically, the nodules were composed of enlarged cortical cells with eosinophilic cytoplasm and nuclear pleomorphism, without mitotic figures. The morphology was consistent with primary pigmented nodular adrenocortical dysplasia (PPNAD). Additional right adrenalectomy was performed for curative treatment of Cushing's syndrome. The pathogenesis of PPNAD is not yet established, though, a defect on chromosome 16 was recently suggested. Since our patient had a malignant melanoma earlier in her history, the PPNAD may be a manifestation of the Carney complex.

Cushing's syndrome due to primary pigmented nodular adrenocortical disease--a case report reviews of the literature

Primary pigmented nodular adrenocortical disease (PPNAD) is a rare cause of Cushing's syndrome in infants, children and young adults. It is characterized by non-adrenocorticotropic hormone-dependent hypersecretion of cortisol by multiple, pigmented nodules of hyperplastic adrenocortical cells. Biochemically, PPNAD is characterized by elevated levels of plasma and urinary cortisol that are not suppressed by high doses of dexamethasone (8mg/d for 2 days). Pathologically, the adrenal glands contain multiple dark brown or black nodules and the intervening cortical tissue is atrophic. Recognition of this diagnosis, although rare, is important, as bilateral adrenalectomy is the treatment of choice. We experienced a case of Cushing's syndrome due to primary pigmented nodular adrenocortical disease and report it with reviews of the literature.

Multiple endocrine neoplasia: how many syndromes?

The phrase multiple endocrine neoplasia (MEN) generally denotes an association of tumors so specific as to constitute a syndrome. Three well-recognized such syndromes exist. All are autosomal dominant traits and all have been tentatively mapped to specific chromosomes. Other purported endocrine tumor syndromes have been suggested either as new entities or as subtypes of the existing MEN syndromes. The evidence in favor of these contentions is examined critically. Only one "new" association, that of pheochromocytomas and islet cell tumors, seems reasonable, and even in this setting, some relatives have had manifestations of von Hippel-Lindau syndrome. There is no compelling reason why such conditions as von Hippel-Lindau syndrome, peripheral neurofibromatosis, McCune-Albright syndrome, and others should be reclassified as MEN syndromes, although awareness of their collective endocrine abnormalities is clinically important.

Primary adrenocortical micronodular dysplasia: enzyme histochemical and ultrastructural studies of two cases with a review of the literature

The adrenal glands from two patients with primary adrenocortical micronodular dysplasia (PAMD) were studied (no. 1, a 23-year-old man with cardiac myxomas and sarcoidosis; no. 2, a 16-year-old girl). The PAMD cells showed intense activity of 3 beta-hydroxysteroid dehydrogenase (3 beta DH), succinate DH, glucose-6-phosphate DH, alkaline phosphatase (AlPase), and other DHs and lysosomal hydrolases, giving a characteristic staining pattern. The staining patterns correlated well with ultrastructural findings. The larger adrenals (no. 1: 16.6 g) were associated with larger black nodules and internodular cortex (INC) with fairly well-retained enzyme activities, and contained cell clusters and single cells with intense AlPase activity with the appearance of PAMD nodules in the buds. The smaller adrenals (no. 2: 5.4 g) were associated with smaller black/yellow nodules, and had INC with weaker enzyme activity. Analysis of descriptions of INC in 25 previously reported cases revealed that the larger adrenals (more than 10 g) had less atrophic INC than the smaller ones. The characteristic enzyme pattern in PAMD cells explains the paradox that PAMD adrenals smaller than normal can cause Cushing's syndrome, and may be useful for investigating neoplastic and non-neoplastic counterparts in other adrenal lesions. The relationship between PAMD cells and INC is not simply one of autonomy versus atrophy, and both cell types may be stimulated by a certain common trophic factor. Thus, PAMD belongs to the category of hyperplasia.

Primary pigmented micronodular disease of the adrenals

Primary pigmented micronodular disease is a peculiar form of ACTH-independent Cushing's syndrome characterized by the familial occurrence, the frequent association with malformations and the pathological adrenocortical picture consisting in micronodules with cellular deposition of lipofuscinic pigment. We describe here a case occurring in a 14-year-old girl.

Autoimmune involvement in Cushing syndrome due to primary adrenocortical nodular dysplasia

Cushing syndrome due to primary adrenocortical nodular dysplasia was diagnosed in two patients, aged 3 years 9 months and 9.5 years. Subsequently, adrenalectomy was performed and followed by steroid replacement. In both cases, the adrenals were normal or only slightly enlarged and showed adrenocortical nodular dysplasia histologically. Small lymphocytic infiltrates consisting of T-cells and class II MHC positive macrophages were present in adrenal specimens of both the patients. Samples of protein A sepharose purified serum immunoglobulins from both children stimulated adrenocortical DNA synthesis and cortisol production in cultured guinea-pig adrenal segments in vitro in a dose dependent fashion. Adrenal stimulating immunoglobulins were also demonstrated in serum specimens of both patients' mothers. However, none of them had overt signs of adrenal disease. Our data support the view that autoimmune mechanisms may be involved in primary adrenocortical nodular dysplasia.

Familial Cushing's syndrome due to nodular adrenocortical dysplasia. A putative receptor-antibody disease?

Two sisters aged 13 and 19 years suffering from familial Cushing's syndrome due to nodular adrenocortical dysplasia are described. Pituitary adrenocortical function tests indicated the presence of adrenal autonomy. Adrenal scintigraphy showed bilateral symmetrical uptake indicating the bilateral character of the autonomous process. Complete adrenalectomy was performed in both girls. The adrenals were of about normal weight showing numerous dark brown pigmented nodules and small perivascular lymphocytic infiltrates. Serum immunoglobulin preparations obtained from both girls stimulated adrenocortical cell growth in a cytochemical bioassay system. It is proposed that circulating growth factors may be involved in the pathogenesis of the disease.

Histopathology and ultrastructure of primary adrenocortical nodular dysplasia with Cushing's syndrome

The characteristic adrenal lesions of five patients with bilateral primary adrenocortical nodular dysplasia and Cushing's syndrome developing in adolescence are presented histopathologically, and in two cases ultrastructurally. Two of the patients were siblings with additional extra-adrenal lesions such as pigmented spots on the face, myxoid cutaneous tumours and in one case familial cardiac myxoma. The adrenals were small with an uneven surface due to numerous small brown to black pigmented nodules in the inner cortex. The nodules were composed of eosinophilic giant cells filled with lipofuscin granules. The familial cases in addition revealed a pronounced disorganization of the adrenocortical architecture with capsular disruption and infiltration of periadrenal fatty tissue. The early onset of Cushing's syndrome in the second decade, the bilateral involvement of adrenal glands despite ACTH independence and the familial occurrence in combination with other peculiar rare lesions are strongly suggestive of a malformative process of the zona reticularis of the adrenal glands.

Primary adrenocortical nodular dysplasia with Cushing's syndrome and cardiac myxomas. A peculiar familial disease

In a family with 4 children, 2 had slowly developing Cushing's syndrome and were adrenalectomized between the ages of 18 and 28 years. As in other cases with familial Cushing's syndrome, primary adrenocortical nodular dysplasia, the so-called adrenocortical adenomatosis, was demonstrated. The brother, now 39 years old, is in good health. The sister, however, died at the age of 36 years. Autopsy revealed a cardiac myxoma of the left atrium. A cardiac myxoma had been found incidentally at autopsy of these two patients' oldest brother, a boy who died at the age of 4 years. Both siblings with Cushing's syndrome presented additional Peutz-Jegher-like hyperpigmentation and myxomatous tumours of the skin. Identical observations of familial adrenocortical nodular dysplasia, Cushing's syndrome and cardiac myxomas have not been reported to date. However, the familial occurrence of cardiac myxomas and adrenocortical dysplasia in combination with bilateral large cell calcifying Sertoli cell tumours of the testis has been published recently.

Familial congenital Cushing's syndrome due to bilateral nodular adrenal hyperplasia

Two siblings with congenital Cushing's syndrome due to bilateral nodular adrenal hyperplasia are described. The older, a boy, presented with severe hypertension and died soon after subtotal adrenalectomy. His sister, who had clitoral enlargement and showed persistent hyponatraemia, had a two-stage total adrenalectomy and is still alive. Investigations in the second case showed grossly elevated urinary cortisol metabolites, 17-oxosteroids and 3 beta-hydroxy-5-ene-steroids. These were not suppressed by dexamethasone, and plasma ACTH was undetectable, indicating that the disorder was not due to excessive ACTH secretion. Cell culture studies on the resected adrenals failed to demonstrate an abnormal pattern of steroid synthesis in vitro, and normal trophic responses were obtained with 1-24 ACTH and monobutyryl cyclic AMP. No stimulation of steroid synthesis was obtained with a range of polypeptide hormones, and the cause of the adrenal hyperplasia remains unknown.

Familial Cushing Disease

A 28-year-old woman and her niece presented with manifestations of the Cushing syndrome. Endocrine studies, including small-and large-dose dexamethasone-suppression test confirmed the diagnosis of pituitary ACTH excess. The first patient had a sella of normal size and went into clinical and hormonal remission after external pituitary irradiation, and she has remained well of follow-up for 9 years. The niece had an enlarged sella turcica on tomography and is receiving a course of external pituitary irradiation.