We investigated spironolactone bodies of the adrenal gland within a recent 2 year period in patients with hyperaldosteronism. Spironolactone bodies occur in the adrenal gland secondary to spironolactone treatment  but have yet to be investigated in patients treated with eplerenone, a newer aldosterone antagonist.
The incidence of spironolactone bodies within the adrenal gland in contemporary patients taking spironolactone or eplerenone is unknown. In studies published between 1981 and 1985, inclusions were found within 74-100% of patients with primary hyperaldosteronism that were pharmacologically treated with spironolactone [3, 5–7]. We detected inclusions in only 33% (4/12) of patients with primary hyperaldosteronism treated with spironolactone and/or eplerenone, much lower than prior studies. Remarkably, 50% of patients treated with spironolactone had inclusions while no patients using eplerenone alone had inclusions. It is possible that the release of eplerenone in 2002 and its subsequent preferred use due to less undesirable side effects have decreased the incidence of spironolactone-like bodies.
The spironolactone bodies in some of our patients persisted much longer than the duration for which spironolactone bodies are thought to occur. Spironolactone bodies decrease over time as spironolactone continues to be administered [6, 8]. Conn et al. found the number of spironolactone bodies peaked 4-6 weeks after the start of treatment after which there was a marked decrease, with a third of patients treated for 100-170 days having no detectable bodies . These authors suggested that the existence of bodies gradually diminishes to zero by 170 days . However, in our study, 67% of patients treated with spironolactone alone for over 100 days had bodies and 2 patients treated for over 270 days were found to have either diffuse or focal bodies. The effect of dosage on the persistence of bodies is unknown, but it is of note that in the report by Conn et al., patients with no inclusions received higher dosages of spironolactone . Spironolactone bodies eventually disappear if medication is discontinued [6, 8]. Authors have shown that discontinuation of spironolactone 18-97 days before surgery results in no identifiable inclusion bodies [6, 8]. However, patient 1 in our study discontinued medications for more than 3 weeks and yet inclusions were found. Eplerenone administration may have resulted in these bodies occurring longer than expected.
The ultrastructural morphology of typical spironolactone bodies show scroll-like concentric laminations of membranes with an electron-dense core [1, 2, 5]. Inclusion bodies with unusual histologic features were identified in 1 of our patients and were subsequently examined ultrastructurally, showing a spectrum of findings. A few bodies resembling typical spironolactone bodies were present but there were also inclusions that had the same scroll-like appearance but did not have a visible electron dense core typical for fully-developed spironolactone bodies. Additionally identified were dense inclusions that did not have the concentric laminations or any membrane typical of spironolactone bodies. The specificity of spironolactone bodies for spironolactone treatment is under question. Several researchers have stated that these bodies appear exclusively in aldosterone-producing cells [8, 9]. Kovacs et. al concluded that spironolactone bodies are not exclusively due to spironolactone treatment based on the presence of similar “fingerprint-like bodies” elsewhere in the adrenal cortex secondary to treatment with other drugs .
Spironolactone bodies have been histologically depicted in the literature as typically solitary eosinophilic bodies surrounded by a clearing within a single cell . However, 1 of our specimens histologically contained numerous inclusions which ultrastructurally were composed of both typical spironolactone bodies and membrane-less electron-dense inclusions in individual cells. Mete and Asa described similar membrane-less electron-dense inclusions in a patient with an adrenal cortical adenoma . Unlike our case, their patient was not treated with any aldosterone antagonist and did not have any typical spironolactone bodies in that the inclusions were not concentric or laminated . The bodies that these authors found were multiple per cell and histologically appeared similar to those we identified. Of note, formalin-fixed paraffin embedded tissue was used. Formalin-fixed paraffin embedded tissue has been found by previous studies to be suboptimal for ultrastructural examination and in 1 of our patients only revealed scroll-like inclusions that lacked electron dense cores [12, 13].
The location in which spironolactone bodies are found is variable. Of our 3 patients that had an adrenal cortical adenoma with inclusions bodies, 2 had inclusions only in the tumor, while 1 had bodies predominately in the tumor but also in the non-neoplastic adrenal tissue adjacent to the tumor, mostly in the zona fasciculata and rarely in the zona glomerulosa. In 1 patient with nodular cortical hyperplasia and bodies, the inclusions were confined to the zona glomerulosa. Similar to our results, most authors have identified bodies in the tumor only, while others have found bodies in the tumor and adjacent tissue [3, 6, 11].
Typical spironolactone bodies are described to be Luxol fast blue positive and PAS negative [2, 3]. They are hypothesized to originate from the smooth endoplasmic reticulum [2, 3, 14]. The inclusion is thought to be rich in phospholipids due to Luxol fast blue staining [2, 3]. The concentric laminations have been demonstrated to contain aldosterone . However, we found the bodies to be negative for Luxol fast blue and positive for PAS. Mete and Asa also reported similar Luxol fast blue negativity and PAS positivity . Future studies are needed to further investigate the contents of these inclusions using more sophisticated techniques.