A 53-year-old woman with Cushing's disease and a pituitary tumor

Pituicytoma Associated with Suspected Cushing’s Disease: Two Case Reports and a Literature Review

(1) Background: Pituicytomas are rare gliomas located in the neurohypophysis or infundibulum. A misdiagnosis of pituicytoma as pituitary adenoma is common because of similar location and occasional endocrine disturbances. (2) Case presentation: We present two cases with the comorbidity of pituicytoma and Cushing’s disease (CD). Case 1 is that of a 51-year-old woman, the first reported case of the comorbidity of pituicytoma, CD, and central diabetes insipidus. She received a diagnosis of CD and central diabetes insipidus. After transsphenoidal surgery, histopathology confirmed the diagnosis of pituicytoma and adrenocorticotropin-secreting microadenoma; case 2 is that of a 29-year-old man who received a biochemical diagnosis of CD, but he received a histopathological confirmation of only pituicytoma. Both patients achieved a remission of hypercortisolism without relapse during the follow-up, but they developed hypopituitarism after surgery. We also reviewed all published 18 cases with the comorbidity of pituicytoma and any pituitary adenoma. (3) Conclusions: Pituicytoma might present pituitary hyperfunction disorders such as CD or acromegaly, with or without pathologically confirmed pituitary adenoma. CD is the most common hyperpituitarism occurring concurrently with pituicytomas. The remission rate and hypopituitarism after surgery seem similar or slightly lower in CD than in common pituitary adenomas, but the long-term prognosis is unexplored.

Clinical-Pathological, Immunohistochemical, and Genetic Characterization of a Series of Posterior Pituitary Tumors

Posterior pituitary tumors are supposed to represent the morphological spectrum of a single entity. Herein, we report the clinical-pathological, immunohistochemical, and genetic features of 5 spindle cell oncocytomas (SCOs), 3 pituicytomas, and 1 granular cell tumor (GCT). SCOs had the highest local invasiveness and affected older subjects. The 3 histotypes differed in the content of spindle cells (predominant in pituicytoma and absent in GCT), presence of lymphocytic infiltrate (in SCO and GCT, but not in the pituicytoma) and EMA/GFAP staining (negative in GCT; EMA-positive/GFAP-negative in 4/5 SCO and GFAP-positive in 3/3 pituicytomas). Three SCOs and 1 pituicytoma analyzed with next-generation sequencing had no mutations in 409 genes. However, 1 SCO had previously unreported homozygous deletion of CDKN2A/B and another of SMARCA4, SMARCB1, and NF2. All 3 SCOs had loss of heterozygosity of chromosome 1p, while the pituicytoma had chromosome 19 homozygous loss and chromosomes 10, 13q, and 18q loss of heterozygosity. Since 1p and 13q losses were previously reported in 1 pituicytoma and 1 SCO, respectively, our data demonstrate that posterior pituitary tumors share common genetic alterations. The possibility that posterior pituitary tumors are SMARCA4/SMARCB1-deficient should be kept in mind in the differential diagnosis toward other entities.

Adenohypophyseal hyperfunction syndromes and posterior pituitary tumors: prevalence, clinical characteristics, and pathophysiological mechanisms

Posterior pituitary tumors are rare nonneuroendocrine neoplasms originating in the neurohypophysis that lack hormonal secretory capacity. Surprisingly, these tumors are relatively frequently associated with adenohypophyseal syndromes of hormonal hypersecretion such as Cushing's disease and acromegaly. Fifteen cases of posterior pituitary tumor associated with hypercortisolism have been reported to date, 13 of them were pituicytomas (Pi) and 2 were granular cell tumors (GCT). Six patients with posterior pituitary tumor associated with acromegaly have been reported (4 Pi and 2 GCT). The main forms of clinical presentation and the possible pathophysiological mechanisms of this association are reviewed.

A rare case of pituicytoma presenting with severe Cushing disease: A case report and review of literature

RATIONALE

Pituicytomas are exceptional rare tumors in the sellar and suprasellar regions with clinical manifestations, such as headache, visual disturbance, hypopituitarism, and decreased libido. Unlike that of common pituitary adenoma, the association between pituicytoma and Cushing disease (CD) is extremely rare. There were only 6 reported cases till now. In the current study, we describe an unusual case of pituicytoma associated with severe CD with a recurrence-free follow-up period of 49 months.

PATIENT CONCERNS

A 32-year-old woman was referred to our hospital with moon face, central obesity, and purple stripes on the lower limbs.

DIAGNOSES

The plasma cortisol level was 1122 nmol/L. The low-dose dexamethasone suppression test failed to suppress plasma cortisol. This test provided evidence of nonpituitary-dependent CD. However, magnetic resonance imaging demonstrated a sellar mass measuring approximately 7.6 × 5.7 mm. The patient was diagnosed with pituitary microadenoma. Histopathological analysis of the tissue sections based on the findings from the immunohistochemical staining diagnosed it as pituicytoma.

INTERVENTIONS

Transsphenoidal surgery was performed to remove the pituitary mass.

OUTCOMES

Within 2 months postoperatively, the patient's blood pressure and cortisol level decreased gradually and normalized on the 6th month when other symptoms of CD also disappeared. The patient is presently free from recurrence 49 months after the initial diagnosis.

LESSONS

Based on the postoperative remission, CD was caused by pituitary disorders. A reasonable assumption is that an extremely small coexisting adenoma was not detected by the surgeon and washed out during the dissection. Another possible explanation might be the mass effect caused by this intrasellar lesion.