Keywords
sellar plasmacytoma - multiple myeloma - parasellar mass - differential diagnosis
Palavras-chave
plasmacitoma selar - mieloma múltiplo - massa parasselar - diagnóstico diferencial
Introduction
Plasmacytomas of the sellar region were first reported in 1970 by postmortem pathologic
diagnosis, an observation that predates a case from 1977 that was previously attributed
as the first.[1] They are rare tumors localized on the sellar region arising from plasma cells.[2] It is believed that the entity originates from the surrounding mucosa of the sellar
region and clivus, which can be locally aggressive.[3] Plasmacytomas are often misdiagnosed as adenomas due to the rarity of this disease
and the limited clinical experience of entity in this location. The pathological study
shows distinct plasmacytoid features, including prominent nucleoli. Another differential
diagnosis is chordoma. We report the case of a patient diagnosed with sellar plasmacytoma
and associated hypopituitarism followed by the discovery of multiple myeloma.
Case Report
A 63-year-old female with well-controlled hypertension presented with a 5-month frontal
headache and 3-month impaired visual acuity, worse in the left eye. The admission
neurological exam was notable for a slowly reactive left pupil and left CN III palsy,
with ptosis. Computed tomography (CT) imaging demonstrated homogeneous expansive lesion
with epicenter in the clivus, invading the sphenoid sinuses and with erosion of dorsum
sellae and anterior clinoids bilaterally ([Fig. 1D]). Selar magnetic resonance imaging (MRI) revealed a 4.6 × 4.6 × 3 cm homogeneously
contrast enhancing lesion. There was extension into the bilateral cavernous sinuses,
surrounding the cavernous carotid artery bilaterally, and into the sphenoidal sinus,
sellar region, optic canal, and superior orbital fissures ([Figs. 1A], [1B] and [1C]). Endocrine evaluation demonstrated mild hyperprolactinemia [43.78 ng/dl (5.18–26.53
ng/dl)], hypocortisolemia (3.4 ug/dl [3.7–19.4 ug/dl]) and low T4 level (0.57 ng/dl
[0.7–1.8 ng/dl]) characterizing panhypopituitarism. We found no evidence of renal
insufficiency, anemia, bone pain, or hypercalcemia. The patient was diagnosed presumptively
with a nonfunctioning pituitary macroadenoma and underwent endoscopic endonasal transsphenoidal
approach for resection of the lesion. However, because of clinically important hemorrhage,
the procedure was aborted after resection of ∼ 30% of the mass. After the surgery,
there was mild improvement in visual acuity. Three weeks after hospital discharge,
the patient presented atraumatic lumbar and hip pain. She underwent a hip MRI that
found multiple heterogeneous osteolytic lesions affecting the pelvic bones and proximal
femurs, as well as hip joint effusion. Immunoglobulin electrophoresis revealed monoclonal
IgA/Kappa peak. The final surgical pathology evaluation of sellar mass confirmed immunopositive
expression for Kappa light chain (CD138 and Kappa positives) consistent with plasmacytoma
([Fig. 2C] and [2D]). It was negative for Lambda chain, chromogranin, and CAM 5.2. The bone marrow biopsy
showed no obvious finding of plasma cell proliferation.
Fig. 1 Contrast-enhanced magnetic resonance imaging scan showing a homogeneously enhanced
lesion centered in the clivus, with extension into the sphenoid sinus and bilateral
cavernous sinus (A, B e C). Computed tomography scan showing the destroyed clivus and the invaded sphenoid
sinus (D).
Fig. 2 Pathological study revealing proliferation of plasmacytoid cells with abundant basophilic
cytoplasm, perinuclear hof, round eccentric nuclei, “clock face” chromatin and indiscernible
nucleoli (A and B). The immunohistochemical study revealed tumor cells positive to CD138 (C) and kappa chain (D).
Discussion
The most prevalent sellar/parasellar tumor is pituitary adenoma, which presents more
often with visual field deficits than cranial neuropathies. Another condition that
should be considered for differentiation is chordoma.[3] Lee et al.,[2] after reviewing 70 cases of sellar plasmacytoma (including 65 cases reported from
literature), found the following results: slight predominance in male subjects (57%
males vs 43% females), median age of 59 years old, and hyperprolactinemia in 38% of
the patients (median level 36.7 ng/mL). The majority of the patients presented with
mass effect symptoms, including headaches in 70%, cranial nerve palsies in 65%, and
visual disturbances in ∼ 80%. DiDomenico and Ampie et al.,[1] in a review of 31 cases (including a new described), found a predominance in male
subjects (55% vs 45%), and median age of 61 years old. The cranial nerve more affected
is the abducens.[1] The case reported was a woman, slightly older, with clinical presentation similar
to that described in the literature. The endocrinological pattern differed, as it
describes hypopituitarism in only ∼ 15% of cases. Our case presented with panhypopituitarism
and hyperprolactinemia, the last due to stalk effect. It is unusual to find well preserved
anterior pituitary function in cases of pituitary adenoma with extensive sellar fossa
and clivus destruction.[3] The size of the tumor also differed from the studies reviewed. The mean was 3.4 cm
(ranging from 0.9–3.9 cm, n: 12),[1] while the tumor described was 4.6 cm in its greatest extent. To all the references,
sellar plasmacytoma have a greater propensity for cavernous sinus invasion and erosion
of the parasellar bone, including the cranial nerve foramina.[1] Light microscopy examination might not always be helpful in the differential diagnosis
of a parasellar mass, because the features of poorly differentiated plasma cells sometimes
resemble the profile of an atypical pituitary adenoma, and immunohistochemical staining
is required for definitive diagnosis of a plasmacytoma,[3] as it happened in our case. Nearly half of the patients in their study initially
presented with sellar plasmacytomas and ultimately had a subsequent diagnosis of multiple
myeloma at full work-up or on follow-up.[1] J. Lee et al.,[2] however, found only 37% of the patients diagnosed concurrently with myeloma on presentation
of the parasellar plasmacytoma. Our case developed other symptoms that suggested the
diagnosis of multiple myeloma just a few weeks after the procedure of partial resection
of the sellar mass, even before the immune histopathological diagnosis.
Conclusion
Despite being rare, plasmacytoma should be considered as a possible diagnosis of sellar
mass. It is found mainly in men, presenting with headache, diplopia, visual deficit,
CN palsy (e.g., CN VI), imaging with cavernous sinus invasion and erosion of the parasellar
bone. Increased awareness of this rare tumor and its clinical features can help clinicians
to develop an appreciation for the importance of accurately diagnosing and effectively
managing patients with sellar/parasellar plasmacytomas.
Highlights
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Sellar plasmacytoma should be considered as differential diagnosis of sellar masses.
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Sellar plasmacytoma is more common in elderly men.
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The most common symptoms are headache and diplopia, due to cranial neuropathies.
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Sellar plasmacytoma can present before diagnosis of multiple myeloma.
