Increased MIB-1/Ki-67 Labeling Index as a Predictor of an Aggressive Course in a Case of Prolactinoma

Prolactinoma extension as a contributing factor in dopamine agonist-induced CSF rhinorrhea: a systematic review of the literature

BACKGROUND

Dopamine agonist-induced cerebrospinal fluid (CSF) rhinorrhea is an uncommon treatment-related complication arising in 6.1% of prolactinoma patients treated with dopamine agonists. Locally invasive prolactinomas may create CSF fistulae through formation of dural and osseous skull base defects. Tumor shrinkage secondary to dopamine agonist therapy unmasks skull base defects, thus inducing CSF rhinorrhea. In these cases, repair of the leak may be achieved through collaborative surgical intervention by rhinologists and neurosurgeons. Multiple variables have been investigated as potential contributors to the risk of CSF rhinorrhea development in medically treated prolactinoma patients, with little consensus.

OBJECTIVE

The primary aim of our study was the characterization of risk factors for CSF rhinorrhea development following dopamine agonist treatment.

METHODS

A systematic review of the literature was conducted to identify cases of CSF rhinorrhea following dopamine agonist treatment of prolactinoma. The clinical history, radiographic findings and treatment outcomes are discussed.

RESULTS

Fifty-four patients with dopamine agonist-induced CSF rhinorrhea were identified across 23 articles published from 1979 to 2019. Description of diagnostic imaging [computed tomography (CT)/magnetic resonance imaging (MRI)] was not provided for 18/54 subjects. For the 36 cases that described prolactinoma appearance on CT or MRI, invasion of the cavernous sinuses was reported in 13 (36.1%) and invasion of the sphenoid sinus was reported in 18 (50%).

CONCLUSION

Based on our systematic review, we propose that CT findings of osseous erosion of the sella or the anterior skull base may predict dopamine agonist-induced CSF rhinorrhea. We recommend obtaining a thin-slice CT of the sinuses in cases with MRI evidence of sphenoid involvement.

Macroprolactinoma with secondary resistance to dopamine agonists: a case report and review of the literature

BACKGROUND

Resistance to dopamine agonists is not uncommonly seen in prolactinomas. However, development of resistance to dopamine agonists after an initial period of robust treatment response is rare, and only 39 cases have been reported in the past four decades. We describe a Chinese man with this rare condition and explored the postulated mechanisms that may explain this phenomenon. We compiled similar cases that were previously reported and compared their etiology, progress, and response to treatment. On the basis of these cases, we derived a list of differential diagnoses to consider in patients with secondary resistance to dopamine agonists.

CASE PRESENTATION

A 63-year-old Chinese man presented with blurred vision and was subsequently diagnosed with a macroprolactinoma. He had initial response to cabergoline but developed secondary resistance to it after 5 years. The prolactinoma continued to grow, and his serum prolactin remained markedly elevated despite adherence to escalating dosages of cabergoline up to 6 mg/week. The patient finally underwent transsphenoidal surgery and was found to have a sparsely granulated lactotroph tumor with Ki-67 index of 5%. Postoperatively, there was improvement in his serum prolactin level, although he still required treatment with cabergoline at 6 mg/week.

CONCLUSIONS

Surgery can facilitate disease control in patients with prolactinomas that develop secondary resistance to dopamine agonists. Malignant prolactinoma is an important differential diagnosis in this group of patients, especially when serum prolactin remains markedly elevated despite resolution or stability of the primary pituitary lesion, suggesting a metastatic source of prolactin secretion.

[Changes in the morphological structure of giant prolactinoma during treatment with cabergoline]

Currently, cabergoline therapy is the main method of treatment with prolactin. The use of the drug in most cases leads to tumor regression, normalization of prolactin levels and restoration of gonadotropic function. The mechanism of its impact on tumor cells in vivo, which is dynamically traced in the same human tumor, is the case of considerable interest. We observed a 30-year-old patient who was operated on twice for a giant prolactinoma before and on treatment by cabergoline. The morphological study after the first surgery (before introducing of cabergoline therapy) revealed a prolactin-positive pituitary tumor with a Ki-67 labeling index of 8% and with strong expression of dopamine type 2 receptors (D2R), CD31 and CD34. After 4 months, during which the patient received cabergoline at a dose starting from 0.5 mg to 1.5 mg per week, a second transsphenoidal surgery was performed with subtotal removal of residual tumor tissue. During the morphological study of the second biopsy sample, the tumor retained a pronounced immunopositivity to prolactin and D2R, with a decrease in the labeling index Ki-67 to 2%, as well as a decrease in the expression of CD31 and CD34. Subsequent cabergoline therapyresulted in persistent normoprolactinemia, restoration of androgen (and reproductive) status, and no tumor recurrence over a 10-year period on cabergoline treatment. Thus, one of the mechanisms of effect of cabergoline that leads to tumor regression is a decrease in the proliferative index and angiogenesis of the tumor.

Decrease of Proliferative Potential and Vascular Density of Giant Prolactinoma in Patients Treated with Cabergoline

Introduction:

Currently, cabergoline therapy is the main treatment for prolactinomas. The use of the drug in most cases leads to regression of the tumor, normalization of prolactin (PRL) levels, and restoration of gonadotropic function. The mechanism of its action in tumor cells “in vivo” tracked in dynamics in the same human tumor is of considerable interest.

Materials and Methods:

A 30-year-old male was admitted to N.N. Burdenko National Medical Research Center of Neurosurgery. An magnetic resonance imaging (MRI) revealed a giant pituitary adenoma. The level of PRL was more than 5000 mU/l (30-360) (serum dilution was not used to determine PRL). Transcranial microsurgical removal of the tumor was performed. He was treated by cabergoline after surgery. Endoscopic transsphenoidal approach was repeated with subtotal removal of the rest of the tumor. Morphological and immunohistochemical studies of the tumor were done.

Results:

A morphological study revealed PRL-positive tumor with a Ki-67 LI of 8% with a distinctive expression of D2R, CD31, and CD34 markers. Control MRI in 3 months after surgery revealed remnants of a tumor of endoinfrasellar localization, the tumor remainders were found in endoinfrasellar localization. The tumor retained pronounced immunopositivity to PRL and D2R and a decrease in the Ki-67 to 2% and in the expression of CD31 and CD34. Subsequent therapy with cabergoline resulted in persistent normoprolactinemia, restoration of androgenic function, and absence of tumor recurrence during the 10-year follow-up period.

Conclusions:

Cabergoline is an effective treatment for prolactinoma, which leads to tumor regression. One of its mechanisms is the reduction of the proliferative index and tumor angiogenesis.

The Past, Present, and Future Statuses of Formerly Classified "Atypical Pituitary Adenomas": A Clinicopathological Assessment of 101 Cases in a Cohort of More than 1,000 Pure Endoscopically Treated Patients in Single Center

Objective  This study was aimed to assess the clinical aggressiveness of pituitary neoplasms that were previously defined as atypical adenomas. Methods  A total of 1,042 pituitary adenomas were included in the study and 101 of them were diagnosed as atypical adenoma. Demographic characteristics, radiological evaluations, and clinical information were obtained from a computer-based patient database. Cases were categorized as atypical or typical using the criteria listed in 2004 Classification of Tumors of Endocrine Organs. Results  The cure and reoperation rates did not show any statistically significant difference between the typical and atypical adenomas. However, a higher K _i -67 labeling index was found to be associated with a higher rate of reoperation ( p  = 0.008) in atypical adenomas. Of note, cavernous sinus invasion or parasellar extension was found to be associated with lower cure rates in patients with atypical pituitary adenomas ( p  < 0.001 and p  = 0.001, respectively). Conclusion  Although atypical pituitary adenomas are known to be more invasive, this study demonstrated that the reoperation and cure rates are the same for typical and atypical adenomas. Our findings advocate for omitting the use of atypical adenoma terminology based solely on pathological evaluation. As stated in the 4th edition of the World Health Organization (WHO) classification, accurate tumor subtyping, evaluation of proliferation by means of mitotic count and K _i -67 labeling index, and radiological and intraoperative assessments of tumor invasion should be taken into consideration in the management of such neoplasms.

Management of large aggressive nonfunctional pituitary tumors: experimental medical options when surgery and radiation fail

Pituitary adenomas are generally considered benign tumors; however, a subset of these tumors displays aggressive behavior and are not easily cured. The protocol for nonsurgical treatment of aggressive pituitary lesions is less standardized than that of other central nervous system tumors. Aggressive surgical treatment, radiation, dopamine agonists, antiangiogenic drugs, and other chemotherapeutics all have roles in the treatment of aggressive pituitary tumors. More studies are needed to improve outcomes for patients with aggressive pituitary tumors.

Towards an integrated molecular and clinical strategy to predict early recurrence in surgically resected non-functional pituitary adenomas

Pituitary adenomas (PA) are histologically benign tumors of the sella that are capable of recurrence following resection. No mechanism exists to predict accurately the risk of recurrence in patients with PA following successful gross total surgical resection. We used microarray-based gene expression profiling to search for genotypically distinct subgroups of non-functional PA associated with the early recurrent phenotype. Rigorous phenotypic controls were used to select four patients with PA with early (<12 months) recurrence and seven patients with non-recurrent PA for comparative molecular analysis. Seventy genes with differential expression patterns between the phenotypic groups were identified, although this required some relaxation of rigid multiple-testing corrections. While some of these genes may therefore represent statistical false discoveries attributable to limited sample size, the CHL1 gene has a differential expression patterns that suggests a potential role as a predictor of recurrence phenotype. Transcriptome-level differences between early recurrent and non-recurrent non-functional PA appear to be subtle, although CHL1 expression may be a candidate for further study as a class discriminator. This suggests two possibilities with regard to recurrence; (i) that microscopic residual disease unidentifiable either by the surgeon or by current neuroimaging strategies may serve as a focus for early recurrence or that biological differences in recurrence phenotypes may occur outside of the transcriptome. These findings are useful for focusing future investigations into the clinical and biological mechanisms of PA recurrence as well as for development of strategies designed to predict prospectively these recurrence phenotypes.

Dopamine agonist-resistant prolactinomas

The authors' object in this paper was to review the definition, epidemiology, biology, resistance mechanisms, and treatment options for dopamine agonist-resistant prolactinomas (DARPs). Prolactinomas are relatively unique among primary brain tumors in that medical treatment alone using dopamine agonists carries a high probability of disease control or even radiographic and endocrine remission, and thus has replaced surgery as the first line of therapy. Unfortunately, slightly less than 10% of patients with prolactinomas do not experience normalization of their prolactin levels in response to dopamine agonists, and harbor tumors that are resistant to dopamine agonist therapy. A literature review underscores that in male patients these DARPs are more likely to be invasive macroadenomas than dopamine agonist-responsive prolactinomas and that they are also more angiogenic, more proliferative, and more likely to exhibit cellular atypia. Estrogen receptor antagonists and temozolomide are the most commonly applied medical therapies in cases in which resection and radiosurgery have not induced remission of the hyperprolactinemia. Dopamine agonist-resistant prolactinomas exhibit aggressive behavior and tend to be large, invasive, hyperangiogenic tumors with high mitotic indices, which makes their management via surgery, radiosurgery, or alternative medical therapies challenging, thus underscoring the need for novel medical therapies or treatment regimens that target these lesions.

Relevance of Ki-67 and prognostic factors for recurrence/progression of gonadotropic adenomas after first surgery

OBJECTIVE

Gonadotropin-secreting pituitary adenomas carry a high risk of local recurrence or progression (R/P) of remnant tumor after first surgery. The clinical characteristics and the long-term outcome of these silent adenomas, which show no signs of endocrine hyperfunction, differ from those of other types of pituitary adenomas. However, to date, no study has focused specifically on gonadotropic adenomas.

MATERIALS AND METHODS

To identify prognostic factors of R/P of remnants, we studied the postoperative outcome of 32 gonadotropic pituitary adenomas, defined on immunohistochemical staining, according to their clinical and radiological characteristics as well as the Ki-67 labeling index (LI).

RESULTS

The Ki-67 LI failed to provide independent information for the identification of patients at risk of progression of remnants or recurrence. Multivariate survival analysis (Cox regression) showed that neither invasiveness nor remnant tumors nor hyposomatotropism influenced tumor recurrence. The strongest predicting factors of R/P were the antero-posterior (AP) diameter in the sagittal plane (P = 0.014), and the age of the patient at surgery (P = 0.047), with younger patients being at greater risk. Hazard ratios were 2.11 for each 5 mm increase in AP diameter and 0.57 for every 10 years of age.

CONCLUSION

The two simple clinical criteria revealed by our study, the AP diameter of the tumor and the age of the patient, should be helpful in planning clinical management and radiological monitoring after first surgery of gonadotropic adenomas, while awaiting the identification of other pathological parameters.

Reversal of hypogonadotropic hypogonadism with tamoxifen in a patient with hyperprolactinemia resistant to dopamine agonists

OBJECTIVE

To determine the response to tamoxifen in a woman with hypogonadotropic hypogonadism induced by hyperprolactinemia resistant to dopamine agonist drugs.

DESIGN

Case report.

SETTING

Academic fertility center.

PATIENT(S)

A young woman with persistent amenorrhea, symptomatic hypogonadotropic hypogonadism, and hyperprolactinemia.

INTERVENTION(S)

Tamoxifen was administered in addition to bromocriptine.

MAIN OUTCOME MEASURE(S)

Measurements of follicle-stimulating hormone, estradiol, prolactin, and progesterone.

RESULT(S)

Recovery of gonadal-hypothalamic-pituitary axis.

CONCLUSION(S)

Tamoxifen can revert the effects of chronic hypogonadotropic hypogonadism induced by hyperprolactinemia resistant to dopamine agonists.

Relevance of high Ki-67 in pituitary adenomas

Pituitary adenomas are heterogeneous in growth rate, invasiveness, and recurrence. To understand the biological behavior of the individual adenoma more fully, cell proliferation markers such as monoclonal antibodies targeted against the Ki-67 antigen have been applied. The Ki-67 antigen is a protein related to cell proliferation and is expressed in cell nuclei throughout the entire cell cycle. The authors report the case of an extremely rapidly growing pituitary adenoma with cavernous sinus invasion. The lesion, which displayed a high Ki-67 labeling index (LI; 22%), was found in a 54-year-old woman who presented with diplopia and headaches. The patient underwent three transsphenoidal operations in less than 6 months and, ultimately, was treated with fractionated intensity-modulated radiation therapy. The relationships between high Ki-67 LIs and tumor recurrence, invasiveness, and growth velocity in pituitary adenomas are reviewed.