Differential diagnosis of sellar masses

Primary central nervous system lymphoma mimicking pituitary apoplexy: case report

Lymphoma involving the pituitary gland is very rare and usually results from metastatic spread of systemic lymphoma. We present a case of primary central nervous system (CNS) large B cell lymphoma that manifested as pituitary apoplexy. A 45-year-old woman presented with headache, and then rapidly developed a third nerve palsy and bitemporal hemianopsia. Imaging suggested a pituitary macroadenoma, with spontaneous necrosis, extending into the suprasellar region, compressing the optic chiasm and invading the right cavernous sinus. The patient underwent transsphenoidal resection which revealed a vascular, firm tumor. An aggressive decompression of the optic chiasm was performed with complete resolution of both visual fields and third nerve palsy. Final pathology showed B cell lymphoma. Systemic work-up including bone marrow aspiration and CSF studies showed no other foci of lymphoma, and the patient was HIV-negative. Chemotherapy with methotrexate, vincristine, procarbazine, and dexamethasone was administered for primary CNS lymphoma. This is an uncommon diagnosis of which the clinician should be aware in order to tailor surgical intervention and provide early institution of proper therapy.

Primary pituitary lymphoma: a histological, immunohistochemical, and ultrastructural study with literature review

We report the case of a 62-year-old man with headache and left sixth cranial nerve palsy. A computerized tomography scan revealed an osteolytic process involving the sella turcica and clivus. A partial tumor resection was achieved via an endoscopic transsphenoidal approach. Morphologic investigation revealed a diffuse large B cell lymphoma involving pituitary parenchyma. No systemic disease was found upon staging. Primary pituitary lymphoma is extremely rare. An accurate histologic diagnosis is key to successful treatment and a favorable prognosis. The literature is reviewed.

Intrasellar plasmacytoma: an unusual presentation of multiple myeloma

INTRODUCTION

Plasmacytomas are unusual causes of a sellar mass. Occasionally, they can be misdiagnosed as a nonfunctioning adenoma because of radiological and clinical similarities.

LITERATURE REVIEW

We reviewed the pertinent literature and discuss here in the light of an illustrative case of our own.

DISCUSSION

A 70-year-old woman presented with a recurrent hypophysial mass. Initial diagnosis of a nonfunctioning pituitary adenoma was later overruled by a repeat biopsy, which showed a plasmacytoma. The tumor stained positively for CD138 and kappa light chain. Further studies confirmed the diagnosis of multiple myeloma. The patient was successfully treated with radiotherapy followed by systemic chemotherapy. Because they have different therapeutic implications, extramedullary plasmacytomas involving pituitary gland should be considered in the differential diagnosis of a nonfunctioning pituitary mass.

Sellar lymphoma mimicking sphenoid infection presenting with cavernous sinus syndrome

Lymphomas can occur throughout the body, but are relatively rare in the sphenoid region. The clinical presentations are atypical, ranging from nasal symptoms, pituitary hormone dysfunction and neurological impairment. We report a 63-year-old female patient who suffered nasal discharge, retro-ocular pain and left lateral gaze palsy for 3 months. Cranial MRI revealed sellar and suprasellar lesions involving the clivus, cavernous sinus and sphenoid sinus. The patient was treated for chronic sphenoid sinusitis. Histopathological review for possible misdiagnosis was arranged owing to treatment failure 1 month later. The final diagnosis was primary large B-cell lymphoma, which was confirmed by immunohistochemical study and systemic survey. The symptoms of sellar lymphoma resemble those of chronic sphenoid sinusitis. MRI and hematoxylin and eosin histological examination can accurately diagnose most cases. Immunohistochemistry assay is recommended in equivocal cases and provides a more detailed tumor classification.

Autoimmune hypophysitis of SJL mice: clinical insights from a new animal model

Autoimmune hypophysitis (AH) is a rare but increasingly recognized disease of the pituitary gland. Its autoantigens are unknown, and the management is difficult because it is often misdiagnosed as a nonsecreting adenoma. By immunizing female SJL/J mice with mouse pituitary extracts, we established a new mouse model of experimental AH. Immunized mice developed severe lymphocytic infiltration in the anterior pituitary that closely mimicked the human pathology. In the early phase of experimental AH, the pituitary enlarged, consistent with the compression symptoms reported by hypophysitis patients at presentation. In the florid phase, adrenal insufficiency and pituitary antibodies developed, in strong correlation with the pituitary pathology. In the late phase, hypothyroidism ensued, and the pituitary gland became atrophic. Using immune sera as probes in a two-dimensional immunoblotting screen followed by mass spectrometry, we identified several proteins that could function as pituitary autoantigens. These findings provide new insights into the pathogenesis of AH, and establish a platform for developing novel diagnostic biomarkers and therapeutics.

Rare sellar lesions

Sellar masses are associated most commonly with pituitary adenomas. Many other neoplastic, inflammatory, infectious, and vascular lesions, however, may affect the sellar region and mimic pituitary tumors. These lesions must be considered in a differential diagnosis. This article describes the characteristics of rare sellar masses that provide clues to their differential diagnosis.

Pituitary abscess: our experience with a case and a review of the literature

Pituitary abscess is a rare disease. Due to its potentially high mortality and morbidity rate, it should be considered in the differential diagnosis of sellar masses. Despite recent advances in radiological investigations, making a definitive diagnosis preoperatively remains challenging. This 45-year-old Indian gentleman presented with severe throbbing headache for six months. Magnetic resonance imaging of the brain revealed a sellar mass with peripheral enhancement that was misdiagnosed as a pituitary macroadenoma. A trans-sphenoidal excision was done, which surprisingly yielded only pus that was drained accordingly from the lesion. Fungal and bacterial cultures were negative. However this patient subsequently lost complete function of the pituitary gland, resulting in central diabetes insipidus and required permanent hormonal replacement therapy in the deficient endocrine axes. A Medline search was conducted and a review of 24 cases reported in the last 5 years discussed.

Sellar abnormalities in female first-degree relatives

Non-pituitary lesions account for a minority of sellar region abnormalities. We report the unusual occurrence of non-pituitary sellar/suprasellar lesions in a mother and her two daughters. Each of these cases was diagnosed and managed differently, illustrating the relative importance of radiographic imaging, tumor markers and histopathologic examination in the diagnosis and treatment of intracranial disease. The mother had histologically confirmed Rathke's cleft cyst (RCC) with typical radiographic and histologic appearance. One daughter was treated presumptively for germinoma based on characteristic radiographic studies and slightly elevated tumor marker. The other daughter's lesion exhibited radiographic characteristics concerning for pituitary macroadenoma but with slightly elevated germ cell tumor marker, raising the suspicion for germinoma. Biopsy of the intrasellar mass revealed only proteinaceous material and normal anterior pituitary, consistent with cyst content without evidence of neoplasm. Without a clear unifying diagnosis it is difficult to posit an underlying pathology or genetic mechanisms in this unusual set of cases. At least two of the patients had benign cysts. The diagnosis of the third patient is unclear as there was no tissue biopsy. However, it is highly improbable that three female first-degree relatives would develop such lesions in the same brain region simply by chance.

Extranodal NK/T-cell lymphoma presenting as a pituitary mass. Case report and review of the literature

Primary pituitary lymphomas (PPLs) are rare tumors of the central nervous system, and most are of B-cell origin. Extranodal NK/T-cell lymphomas are uncommon neoplasms that are highly aggressive and show a strong association with Epstein-Barr virus. They most commonly affect the nasal cavity and paranasal sinuses; manifestation as a primary pituitary tumor has never been described. The authors report a case of NK/T-cell lymphoma of the pituitary gland and review 17 cases of PPL from the literature. All patients had been evaluated at presentation for clinical, neuroimaging, and histopathological findings. Patients who had systemic lymphoma with secondary involvement of the pituitary gland were excluded. The mean patient age was 55.5 years (range 26-86 years); the male/female ratio was 13:5. The most common presentation was pituitary insufficiency (72%), followed by headache (56%), diplopia (39%), visual loss (28%), and fever (22%). Thirteen patients (72%) exhibited anterior hypopituitarism and seven (39%) had diabetes insipidus at presentation. Magnetic resonance imaging demonstrated enhancing parasellar masses with diffuse enlargement of the pituitary gland (94%), suprasellar extension (44%), cavernous sinus extension (39%), and stalk thickening (22%). Thirteen patients (72%) had B-cell lymphoma, four (22%) had T-cell lymphoma, and one (6%) had NK/T-cell lymphoma. Primary pituitary lymphomas are rare entities with a range of clinical presentations and neuroimaging findings that are unique from those of patients who present with pituitary adenomas. The pathological entity of NK/T-cell lymphoma is distinct, and its course is very aggressive with a poor prognosis.

Sarcoidosis: clinical, hormonal, and magnetic resonance imaging (MRI) manifestations of hypothalamic-pituitary disease in 9 patients and review of the literature

Hypothalamic-pituitary (HP) sarcoidosis has 2 main endocrine manifestations: diabetes insipidus and hyperprolactinemia. We conducted the current study to investigate pituitary dysfunction and perform imaging of the HP area in patients both immediately following diagnosis and after treatment. The study included 6 men and 3 women, with a mean age of 30 years at the onset of sarcoidosis. All patients had both hormonal and magnetic resonance imaging (MRI) HP disorders. All patients had anterior pituitary dysfunction, 7 of them with associated diabetes insipidus. Nine patients had gonadotropin deficiency and 3 had hyperprolactinemia. MRI revealed infundibulum involvement in 5 patients, pituitary stalk thickness abnormality in 5, and involvement of the pituitary gland in 2, associated with other parenchymal brain or spinal cord lesions in 6 patients. All patients had multiple localizations of sarcoidosis, and 5 had histologically confirmed sinonasal localizations. Mean follow-up of the HP disorder was 7.5 years. All patients received prednisone. There was no correlation between the number of hormonal dysfunctions and the area of the HP axis involved as assessed by MRI. Although corticoid treatment was associated with a reduction of radiologic lesions, only 2 patients had partial recovery of hormonal deficiency. In conclusion, hormonal deficiencies associated with HP sarcoidosis frequently include hypogonadism (all patients) and to a lesser degree diabetes insipidus (7 of 9 patients). MRI abnormalities improved or disappeared in 7 cases under corticosteroid treatment, but most endocrine defects were irreversible despite regression of the granulomatous process. Most cases presented with multivisceral localizations and an abnormally high proportion of sinonasal localizations.

An isolated pituitary metastasis as presentation of a differentiated hepatocellular carcinoma mimicking a nonfunctioning macroadenoma

The differential diagnosis of sellar masses may be complex. Metastatic disease constitutes 1% of all pituitary lesions and sometimes mimics the clinical-radiological presentation of pituitary adenoma. The definitive diagnosis usually relies on histology, but occasionally even histological features of pituitary metastasis may resemble those of adenomas. We present a patient initially diagnosed with pituitary adenoma, but whose clinical course finally revealed pituitary metastasis of a hepatocellular carcinoma. The existing literature on this topic is reviewed.

Sclerosing epithelioid fibrosarcoma of the pituitary

Primary pituitary sarcoma in the absence of previous radiation therapy is very rare, only eight cases having been reported. We present the first reported case of sclerosing epithelioid fibrosarcoma of the pituitary, a 56-year-old woman presenting with diplopia and panhypopituitarism. Magnetic resonance imaging showed a 1.2 x 0.4 x 0.5-cm sellar mass invading the right cavernous sinus. Despite surgery and radiation therapy, our patient developed intracranial metastases and died 2 years after the initial diagnosis. Sclerosing epithelioid fibrosarcoma is an infrequently occurring, distinct variant of soft tissue fibrosarcoma. Its immunophenotype includes vimentin and occasionally CD-34, B cell lymphoma-2, S-100 protein, or keratin expression. Although initially thought to be a low-grade lesion, sclerosing epithelioid fibrosarcomas may also behave in a high-grade manner.

Imaging of sellar and parasellar lesions

The sellar and parasellar region is an anatomically complex area where a number of neoplastic, infectious, inflammatory, developmental and vascular pathologies can occur. Differentiation among various etiologies may not always be easy, since many of these lesions may mimic the clinical, endocrinologic and radiologic presentations of pituitary adenomas. The diagnosis of sellar lesions involves a multidisciplinary effort, and detailed endocrinologic, ophthalmologic and neurologic testing are essential. CT and, mainly, MRI are the imaging modalities to study and characterise normal anatomy and the majority of pathologic processes in this region. We here provide an overview of the most relevant MRI and CT characteristics together with clinical findings of pituitary tumors, vascular, inflammatory and infectious lesions found in the sellar/parasellar region in order to propose an appropriate differential diagnosis.

Evaluation and management of pituitary incidentalomas--revisiting an acquaintance

Incidentalomas of the pituitary gland have been described with increasing frequency, paralleling the advances in diagnostic imaging modalities. Several approaches have been proposed in order to appropriately evaluate their impact on patients, some recommending extensive investigations, while others advocate a more focused and potentially more cost-effective approach. The first part of this article will review current data about the prevalence, natural history and potential morbidity associated with these tumors. The second part will focus on imaging and hormonal evaluation of the incidental mass and suggest an updated management algorithm.

Xanthogranuloma of the sellar region

The incidence of diagnosed xanthogranuloma of the sellar region is very low [1, 2, 5, 6]. We report about two cases 1) in a 57-year-old female and 2) in a 5-year-old boy. In both cases radiographic findings revealed an inhomogeneous, contrast enhancing sellar lesion. Histopathology showed the typical features of a xanthogranuloma of the sellar region with cholesterol clefts, lympho-plasmacellular infiltrates, marked hemosiderin deposits, multinucleated foreign body giant cells around cholesterol clefts, accumulation of macrophages and only small epithelial cell clusters [6]. As xanthogranuloma of the sellar region are rarely diagnosed we want to draw attention to this rather unusual diagnosis.

[Nonpituitary tumors of the sellar region]

The pituitary gland, sella turcica and the parasellar region can be involved by a wide variety of lesions, including benign and malignant neoplasms as well as a wide variety of non neoplastic tumor-like lesions. Clinical and radiological aspects could help in the differential diagnosis of these lesions. Nevertheless, in many cases only the histopathological analysis could establish the definitive diagnosis. In this paper, we review the nonpituitary tumors of the sellar region emphasizing the associated hormonal disturbances.

Primary pituitary lymphoma presenting as hypophysitis

A 47-year-old man had suffered from prolonged fever for two months without clinical evidence of infection. Blood biochemistry and endocrine dysfunction indicated that he had pituitary insufficiency. Thorough whole body imaging studies merely identified a 22 x 14 mm mass lesion in the sella turcica. Tumor pathology and special cell marker study revealed the infiltration of atypical T-lymphoid cells and concomitant presence of some B-lymphoid cells. The fever subsided gradually following subtotal tumor resection and steroid supplementation. However, the mass lesion had invaded the cavernous sinus and optic chiasma shortly after surgery. Six months after his initial visit, metastasis lesions in the liver, the left adrenal gland, and retroperitoneal lymph nodes were discovered. In contrast to cells in the pituitary, the pathological investigation of the liver mass confirmed it to be exclusively of T-cell origin. Therefore, it is plausible that the pituitary dysfunction was related to an inflammatory process, namely hypophysitis, as well as the T-cell lymphoma. This case exemplifies the rarely noted condition of primary pituitary lymphoma with concomitant hypophysitis. Clinical diagnosis is indiscernible until the occurrence of systemic tumor metastasis.

Imaging the sella and parasellar region

The anatomy of the sella and parasellar region is discussed. Pertinent ophthalmologic findings and syndromes relating to this anatomic region are described. Pathologic processes, such as pituitary adenoma, pituitary apoplexy, craniopharyngioma, Rathke's cleft cyst, lymphocytic adenohypophysitis, and other such parasellar lesions are discussed along with their ophthalmologic manifestations.

Arachnoid cysts with orbital bone remodeling--two interesting cases

PURPOSE

To describe two cases of arachnoid cyst that altered the bony orbit.

METHODS

Case report.

RESULTS

Cases of unilateral arachnoid cyst are described in two men, both over the age of 60. The patients were evaluated with computed tomography (CT) scans and in each, an arachnoid cyst in the middle cranial fossa caused bone remodeling with exophthalmos in one. These patients were followed clinically and radiographically over a number of years with no change.

CONCLUSION

Arachnoid cysts in the middle cranial fossa have the potential to result in clinically significant proptosis due to bone remodeling of orbital walls. Patients with unexplained proptosis should be evaluated with CT scans to establish the presence of bone remodeling and an arachnoid cyst, which can be confirmed with T2-weighted magnetic resonance imaging (MRI).

Extra-axial brain tumors

Meningiomas, schwannomas, metastases, maldevelopmental cysts, epidermoids, dermoids and bone tumors represent the vast majority of extra-axial brain tumors. The location of extra-axial brain tumors affects treatment planning and predicts their prognosis. Computed tomography and particularly magnetic resonance imaging are used for diagnosis and localization. In this article, the imaging findings of the extra-axial brain tumors are discussed.

Diagnostic and Therapeutic Approach to Pituitary Incidentalomas

OBJECTIVE

To review data on epidemiology, differential diagnosis, clinical, laboratory, and imaging findings, natural history, and management of incidentally discovered pituitary lesions (pituitary incidentalomas).

METHODS

A nonsystematic review was conducted, including articles indexed in Index Medicus that contained reference to incidentally discovered pituitary masses (pituitary incidentalomas).

RESULTS

Both autopsy and sensitive neuroimaging studies (including magnetic resonance imaging) suggest that pituitary incidentalomas are common, affecting approximately 10% of the general population. Although typically small (less than 10 mm in greatest diameter) and clinically silent, some pituitary incidentalomas may be hormonally active or cause mass effects by compressing neighboring structures. In addition, a minority of these lesions may grow over time; hence, long-term follow-up is necessary. Therapeutic interventions, including dopamine agonist therapy (in the case of prolactin-secreting adenomas) or transsphenoidal resection, are indicated in the case of pituitary lesions that are hormonally active, cause mass effects, or increase in size.

CONCLUSION

Pituitary incidentalomas are common and constitute a heterogeneous group with regard to pathologic features, clinical, laboratory, and imaging characteristics, natural history, and growth potential. Currently available evidence suggests that many hormonally nonfunctioning pituitary incidentalomas causing no mass effects can be safely managed by follow-up surveillance. Nonetheless, more data are needed for further elucidation of the natural history of these lesions and for improvement in accurate and noninvasive diagnosis and in prediction of growth potential of pituitary incidentalomas. Improved understanding of the pathogenesis of this heterogeneous group of lesions may also lead to the development of novel, noninvasive therapeutic agents, rationally designed to interact with well-characterized molecular targets.

Intrasellar and parasellar cellular schwannoma

The complexity of the anatomy of the sella turcica and its surroundings accounts for the large number of pathologic entities that may involve this critical area. Intrasellar and parasellar schwannomas are exceedingly rare; only a handful of true sellar tumors of this nature have been reported in the English literature. These lesions may simulate nonsecretory pituitary adenomas clinically and neuroradiologically. Although benign, complete surgical resection of these tumors is usually difficult because of their size, invasiveness, and rich vascularity. From the histopathologic stand point, those cases lacking typical schwannoma histomorphologic features may pose a diagnostic challenge to the pathologist, especially at the time of frozen section examination, because they may resemble other spindle cell neoplasms more common to that location, such as fibrous meningothelial tumors. We report a case of intrasellar and parasellar cellular schwannoma lacking common and reliable neurilemmomatous features, such as the coexistence of cellular Antoni A and loose Antoni B areas, Verocay bodies, and hyalinized thickened vessels. In addition, features infrequently seen in schwannomas were identified in the specimen, including the presence of psammoma bodies, nuclear optically clear pseudoinclusions, and fine intracytoplasmic melanin-like pigment. Ultimately, the use of immunohistochemistry was necessary to achieve a definitive pathologic diagnosis. Cellular schwannoma expands the pathologic differential diagnosis of spindle cell neoplasms of sellar location that the pathologist should have in mind, especially at the time of frozen section examination. The clinical, histopathologic, and neurosurgical aspects of primary cellular schwannomas of the sella turcica are reviewed.

Hemorrhagic Rathke’s Cleft Cyst Presenting as Diplopia

OBJECTIVE

To report a case of uncommon presentation of hemorrhagic Rathke's cleft cyst (RCC) extending into the cavernous sinus, causing diplopia.

METHOD

We present clinical, radiologic, and histologic findings on this patient, and review related medical literature.

RESULTS

A 34-year-old man presented with a 4-month duration of worsening left-sided headache with acute development of diplopia which worsened upon looking to the left. Magnetic resonance imaging identified a left pituitary mass with posterior extension and involvement of the cavernous sinus. Hormone level evaluation revealed a low free thyroxine index and elevated prolactin levels, and normal levels of thyroid stimulating hormone, growth hormone, insulin-like growth factor type 1, and cortisol. The patient underwent transsphenoidal resection of a yellow fibrous mass from the left side of the sella. Tumor tissue pathology was consistent with a RCC that may have undergone secondary hemorrhage and rupture. Postoperatively, this patient developed transient diabetes insipidus, and required levothyroxine therapy for hypothyroidism. The diplopia improved, though he continues to complain of episodic headaches.

CONCLUSION

RCCs are challenging to diagnose, as they can cause symptoms related to enlargement and hemorrhage. Imaging studies and other diagnostic measures may, therefore, describe heterogeneous features. The most common clinical presentation of this disorder is a manifestation of pituitary dysfunction, such as hyperprolactinemia, diabetes insipidus, and, occasionally, apoplexy. These symptoms may be accompanied by headache. Visual disturbances often appear, usually as visual field defects and decreased visual acuity. This case demonstrates that nonpituitary masses such as RCC can hemorrhage and extend into the cavernous sinus, causing acute ophthalmoplegia.

Acute chagas' disease presenting with a suprasellar mass and panhypopituitarism

Although intrinsic pituitary lesions are the most common cause of hypopituitarism, suprasellar masses can produce similar symptoms. The differential diagnosis of a suprasellar mass includes cystic lesions, tumors, granulomatous disease, and infection. The etiology is not always obvious, and despite extensive work-up, may remain elusive. A 28-year-old Mexican man presented with complaints of headache and weakness for two weeks duration. He became increasingly lethargic and an MRI revealed a two centimeter suprasellar mass. Testing of the hypothalamic-pituitary axis suggested panhypopituitarism. He was prescribed treatment with hydrocortisone, DDAVP, and levothyroxine. Open craniotomy and biopsy of the hypothalamus revealed marked inflammation with plasma cells, histiocytes, and small lymphocytes. Light microscopy revealed macrophage-contained leishmania-like organisms although results were not immediately available. Pathological data was consistent with acute infection by Trypanasoma cruzi. Despite supportive efforts, the patient expired two months after presentation. This case illustrates the difficulty of diagnosing and the potential rapid mortality of a suprasellar mass. Because of the wide consideration of etiologies, a tissue diagnosis is needed. However, as this case illustrates, a definitive tissue diagnosis is not always possible, even following biopsy during open craniotomy.

Follicular Thyroid Cancer Presenting as a Sellar Mass: Case Report and Review af the Literature

OBJECTIVE

To describe an uncommon initial manifestation of well-differentiated follicular carcinoma of the thyroid in an unusual metastatic site.

METHODS

We present clinical, laboratory, and imaging findings in our patient and review related data from the literature.

RESULTS

A young healthy woman presented with headache and diplopia. Magnetic resonance imaging of the brain showed a complex mass in the sellar region. Endocrine evaluation was remarkable only for a modestly high serum prolactin level. Transsphenoidal biopsy of the sellar mass revealed metastatic follicular thyroid carcinoma. On subsequent examination, a thyroid nodule was palpated. She underwent total thyroidectomy and ablative therapy with 131I, after which her symptoms gradually subsided and the sellar mass ultimately decreased in size. Although well-differentiated thyroid cancer generally manifests as a thyroid nodule, metastatic disease is present at the time of initial assessment in approximately 1% of cases, and the lungs and the skeleton are the most frequent sites of involvement. Only a few cases of thyroid cancer metastasizing to the sella have been reported. Described cases occurred mainly in elderly patients with previously diagnosed thyroid cancer. The most common malignant tumors that metastasize to the sella and pituitary are lung cancer in men and breast cancer in women. Metastatic tumors frequently manifest with cranial nerve palsies or diabetes insipidus and occur in elderly patients.

CONCLUSION

Follicular thyroid cancer can manifest initially as a distant metastatic tumor in young patients. Metastatic lesions should always be in the differential diagnosis of a sellar mass, even in young patients.

Diagnosis and management of pituitary tumors: recent advances

In recent years, the medical therapy for prolactinomas and GH-secreting adenomas has greatly improved due to the availability of new, highly effective, long-acting dopamine and somatostatin analogues. Although medical therapy has for some time been the first-line approach to prolactinoma management, the incidence of patients requiring surgery for resistance or intolerance/noncompliance is likely to decrease substantially with these new agents. Increasing efficacy and greater ease of administration of somatostatin analogues for GH, and for rare TSH, adenomas are also anticipated to lead to less reliance on surgery and radiation therapy as the primary therapy in these disorders. Although somewhat unclear at this time, GH antagonists hold promise for alternative or adjunct therapy for acromegaly. Given the significant morbidity and mortality associated with acromegaly, these advances are quite encouraging. Unfortunately, little if any progress has been made toward establishing an effective medical treatment for gonadotropin or nonsecreting tumors. However, new approaches to delivery of radiation therapy may reduce some of the inconvenience and risk of this treatment for patients when surgery alone is inadequate. In all of these disorders, the challenge to physicians and their patients remains one of choosing a rational combination of medical, surgical, and radiation therapy. Fortunately, for most patients, control, if not cure, of their pituitary adenoma is a reasonable expectation.

Armadilhas no diagnóstico da hiperprolactinemia

Na abordagem diagnóstica da hiperprolactinemia, três armadilhas ou problemas potenciais merecem uma atenção especial: os incidentalomas hipofisários (presentes em 10% da população adulta à ressonância magnética), o efeito gancho e a macroprolactinemia. O efeito gancho se caracteriza pela presença de níveis falsamente baixos de prolactina (PRL), quando se empregam imunoensaios de dois sítios em pacientes com grandes prolactinomas e hiperprolactinemia muito acentuada. O efeito gancho pode ser identificado através de uma nova dosagem da PRL após diluição do soro a 1:100, quando se observará um aumento dramático do valor da PRL. Ele deve ser excluído em qualquer paciente com um macroadenoma e níveis séricos de PRL <200ng/mL. A macroprolactinemia responde por cerca de 10% dos casos de hiperprolactinemia. Resulta de um excesso de PRL polimérica (macroprolactina ou big big prolactin), cuja biodisponibilidade é diminuída. Assim, a maioria dos pacientes com macroprolactinemia não apresenta os sintomas clássicos da hiperprolactinemia e habitualmente não requerem tratamento.

Best Practice No 172: pituitary gland pathology

This article reviews published evidence on the diagnosis and classification of pituitary gland tumours and the relevance of histological and genetic features to prognosis. Much of the literature is devoted to the histological, ultrastructural, and immunocytochemical classification of pituitary adenomas (extensively supported by multicentre studies), with little consensus on the identification of prognostic features in adenomas, particularly in relation to invasion. There is a lack of correspondence between clinical and pathological criteria to identify and classify invasion, and a need to reassess the nomenclature and diagnostic criteria for invasive adenomas and carcinomas. Recent cytogenetic, genetic, and molecular biological studies have identified no consistent abnormalities in relation to pituitary tumour progression, although many genes are likely to be involved. In light of these uncertainties, an approach to the diagnosis and classification of pituitary adenomas is suggested, based on robust criteria from earlier studies and incorporating provisional data that require reassessment in large prospective studies with an adequate clinicopathological database.

Bacterial Pituitary Abscess: an Unusual Cause of Panhypopituitarism

OBJECTIVE

To describe a case of primary bacterial pituitary abscess manifesting as hypopituitarism.

METHODS

We present the case history, hormonal and bacteriologic data, and findings on imaging studies in a 34-year-old man.

RESULTS

The patient had an 8-month history of intermittent fever, headache, nausea, vomiting, and weight loss. Because a computed tomographic scan of the head showed a cystic sellar mass with ring enhancement, he was referred to our medical center. On physical examination, he showed signs of meningeal irritation and had mild hypotension. Hormonal evaluation revealed evidence of hypocortisolism, hypothyroidism, and hypogonadism. Three weeks after treatment with antibiotics and hormonal replacement, he underwent transsphenoidal surgical exploration and evacuation of purulent material from the sella. On culture, this specimen grew coagulase-negative staphylococci and Propionibacterium granulosum. Nine months later, dynamic testing showed persistent central hypocortisolism, hypothyroidism, and hypogonadism.

CONCLUSION

Bacterial pituitary abscess is rare but manifests similar to other pituitary masses with headaches, visual field defects, and hormonal disturbances. For the correct preoperative diagnosis of this condition, the physician must have a high index of suspicion, and the characteristic ring enhancement must be present on imaging studies.

Primary B-cell lymphoma of the clivus: case report

BACKGROUND

Lymphomas usually present in extranodal sites late in the course of the disease. Moreover, it is uncommon for a primary non-Hodgkin's lymphoma to present with cranial nerve palsies; reports in the literature are rare.

CASE DESCRIPTION

We report the case of a 60-year-old woman with complaints of headache and double vision. MRI revealed an expansive clival lesion without pituitary invasion. An endoscopic transsphenoidal procedure was performed for diagnosis and partial resection of the mass.

CONCLUSION

Primary diffuse large B-cell lymphoma of the clivus is rare. An endoscopic transsphenoidal approach to the skull base is described, along with characteristic clinical, radiologic, and pathologic findings of the lesions.

Pitfalls in pituitary diagnosis: peculiarities of three cases

Due to the increasing availability and sensitivity of diagnostic methods, biochemical and imaging abnormalities of pituitary function and anatomy are becoming more frequent. Hyperprolactinaemia was found in three women without any prolactin (PRL) related clinical features. All three patients had normal libido, regular menses with evidence of ovulation, no galactorrhoea, and normal FSH, LH, TSH and free T4 serum levels. Magnetic resonance imaging (MRI) of the sellar region showed images that were compatible with pituitary microadenomas in all three cases. Due to the discordance between laboratory and clinical features, we searched for the presence of PRL aggregates with high molecular weight and low biological activity (macroprolactinaemia). Initially, we screened with a polyethylene glycol precipitation method, and then confirmed the presence of macroprolactinaemia by chromatography. All three cases screened positive for the presence of macroprolactinaemia. MRI alterations, compatible with pituitary microadenomas, may be due to true microincidentalomas, normal anatomical variations or imaging artefacts. In conclusion, we have described the presence of double diagnostic pitfalls that might lead to unnecessary medical or surgical intervention.

Magnetic resonance imaging and computerized tomography images in a case of pituitary abscess

A 29-year-old male patient with clinical manifestations of panhypopituitarism and diabetes insipidus is presented. The clinical and laboratory evaluation of the pituitary reserve confirmed a total pituitary insufficiency. Computed tomography (CT) scan demonstrated a low-density lesion suggesting a pituitary tumor with suprasellar extension, and magnetic resonance imaging (MRI) revealed a pituitary mass with decreased signal intensity on T1-weighted images and capsular contrast enhancement after gadolinium injection. The surgical procedure was the treatment of choice. During surgery a large amount of purulent material was removed. With light microscopy, chronic non-specific inflammation and a pituitary abscess capsule were demonstrated in the tissue. The results of the cultures revealed coagulase negative staphylococcus. The post-operative course was uneventful and, as the patient was pituitary-deficient, he was on replacement therapy and was being followed-up. Pituitary abscess is an exceptional lesion in the literature and despite the advent of CT and MRI, its preoperative diagnosis still remains difficult. However, the presence of an intrasellar expansive process with liquid center and contrast enhanced outline should suggest the possibility of an abscess. Sellar round cystic mass isointense or hypointense to grey matter on T1, high intensity signal on T2, or opposite pattern with a peripheral rim enhancement following gadolinium injection, and diabetes insipidus may all be suggestive of a pituitary abscess.

[Hormonal dysfunction of nonpituitary lesions from midline and perisellar area]

OBJECTIVE

To analyse clinical and/or laboratorial preoperative hormonal dysfunction, of the nonpituitary intracranial lesions from midline and parasellar area.

METHOD

Forty-four patients were evaluated with nonpituitary intracranial lesions, who had images studies (computed tomography or magnetic resonance) and preoperative basal hormonal level; 16 had preoperative hypothalamus-hypophysial function tests (megatests). These patients were divided in two groups. Group I - 34 lesions from midline: 11 craniopharyngiomas, 8 meningiomas, 3 germinomas, 3 tumors of sphenoid sinus, 2 empty sella syndrome, 2 pylocitic astrocytomas, 1 giant aneurysm, 2 mucoceles, 1 III ventricle diverticulum and 1 Rathke's cleft cyst; Group II - 10 lesions from parasellar area: 9 meningiomas and 1 giant aneurysm.

RESULTS

In group I, 25/34 (73.5%) patients showed laboratorial hormonal deficit (14 without clinical manifestations) 18/34 (52.9%) hyperprolactinemia (5 with galactorreia) and 8 (53.3%) showed growth hormone deficiency in 15 megatests available in this group; 3 (8.8 %) patients presented central diabetes insipidus (CDI). In group II, 6/10 (60%) patients showed laboratorial hormonal deficit (5 without clinical manifestations), 1 (10%) hyperprolactinemia and 1 growth hormone deficiency (single megatest realized in this group); no patient had preoperative CID.

CONCLUSIONS

The presence of nonspecific or poorly valorized clinical manifestations, does not indicate absence of hormonal dysfunction; in this present serie, 19/38 (50%) patients with laboratorial abnormalities, didn't show clinical manifestations. Hormonal dysfunction is frequent in sellar and perisellar nonpituitary lesions, specially involving midline.

Classification of pituitary adenomas

This brief review summarizes various schemes which were introduced to classify pituitary tumors of adenohypophysial origin. Many different classifications were proposed. Pathologists prefer classifications based on the morphologic features of tumor cells. The gold standard is the light microscopic study of hematoxylin-eosin stained sections of formalin fixed and paraffin-embedded tissues. For correlation between hormone production, secretory activity and cytogenesis, immunohistochemical and transmission electron microscopic investigation is needed. We are convinced that in the future, molecular and genetic techniques will also be applied. We present here our five-tier scheme for classification of pituitary tumors which was accepted by the 'World Health Organization International Histological Classification of Tumours'. This classification takes into consideration the clinical and laboratory findings, imaging results, histologic, immunocytochemical and ultrastructural features of tumor cells. Despite several recent attempts to assess the growth rate, aggressiveness and invasiveness of pituitary tumors, more work is required to draw conclusions on their prognosis.

Pituitary lymphoma: a case report and literature review

We report the case of a B-cell type pituitary lymphoma in a 65 year-old male immunocompetent patient who presented with hypogonadotropic hypogonadism and central hypothyroidism and subsequently developed pulmonary lymphoma. Only three cases of pituitary lymphoma have been previously reported, one in a patient with acquired immunodeficiency syndrome, one case of T-cell lymphoma reported in the Japanese literature, and one case of B-cell lymphoma. The previously reported immunocompetent patients presented with signs and symptoms of optic chiasm compression as contrasted to our patient's endocrinologic presentation. B-cell lymphoma of the pituitary gland is a exceedingly rare though distinct clinical entity.

Pituitary incidentalomas

The optimal strategy for hormonal screening of a patient with any incidentally discovered pituitary mass is unknown. The authors' review of the endocrinologic literature supports the view that such patients are at slightly increased risk for morbidity and mortality. This risk implies a benefit of early diagnosis for at least for some of the disorders, suggesting the importance of case finding. Nevertheless, the data in Table 1 illustrate that clinically diagnosed hormone-secreting pituitary tumors are far less common than incidentalomas. Clinically, one cannot accurately determine the approximately 0.5% of patients with incidentaloma who are at increased risk among the vast majority who are not. Given the limitations of diagnostic tests, effective hormonal screening requires a sufficiently high pretest probability to limit the number of false-positive results. This condition is met to varying degrees in the patient with a small incidentally discovered pituitary mass but no signs or symptoms of hormone excess. Even the more common lesions, such as prolactinoma, are relatively rare. [table: see text] Subjecting patients to unnecessary testing and treatment is associated with risk. In addition to its initial cost, testing may result in further expense and harm as false-positive results are pursued, producing the "cascade effect" described by Mold and Stein as a "chain of events (which) tends to proceed with increasing momentum, so that the further it progresses the more difficult it is to stop." The extensive evaluations performed for some patients with incidentally discovered masses may reflect the unwillingness of many physicians to accept uncertainty, even in the case of an extremely unlikely diagnosis. This unwillingness may be driven, in part, by fear of potential malpractice liability, the failure to appreciate the influence of prevalence data on the interpretation of diagnostic testing, or other factors. The major justification for further evaluation of these patients is not so much to avoid morbidity and mortality for the rare patient who truly is at increased risk but to reassure patients in whom further testing is negative and the physician. Physicians must take care not to create inappropriate anxiety in patients by overemphasizing the importance of an incidental finding unless it is associated with a realistic clinical risk. The authors' recommendations are based on currently available information to minimize the untoward effects of the cascade. As evidence accumulates, these recommendations may need to be revised. The benefit of the diagnosis of an adrenal or pituitary disorder must be considered in the context of the patient's overall condition. Additional studies are needed to analyze the clinical utility of hormonal screening for these common radiologic findings. Data from these studies can be used to identify critical gaps in knowledge and to adopt the epidemiologic methods of evaluation of evidence that have been applied to preventive measures. One must be careful to recognize lead-time bias, in which survival can appear to be lengthened when screening simply advances the time of diagnosis, lengthening the period of time between diagnosis and death without any true prolongation of life; and length bias, which refers to the tendency of screening to detect a disproportionate number of cases of slowly progressive disease and to miss aggressive cases that, by virtue of rapid progression, are present in the population only briefly. Physicians must avoid the pitfalls of overestimation of disease prevalence and of the benefits of therapy resulting from advances in diagnostic imaging. Clinical judgment based on the best available evidence should be complemented and not replaced by laboratory data.