Transcript Case Study 55 - University of Pittsburgh

Case Study 64
Kenneth Clark, MD
Question 1
• This is a 32-year-old woman with a history of a
skull-base tumor, status-post resection 2 years
ago. She has recently developed multiple cranial
nerve palsies. MRI and CT scans of the head
revealed recurrent tumor.
• Describe the MRI and CT findings.
Axial T1
Axial T1 + Contrast
Axial CT Scan
Axial T2 FLAIR
Answer
• MRI shows a large expansile skullbase mass
centered within the right aspect of the clivus and
crossing the midline. There is also extensive
involvement of the petrous and mastoid portions
of the right temporal bone and extension into the
dorsum sellae. It shows variegated
isointensity/hypointensity on T1-weighting, mild
heterogeneous contrast enhancement and
diffuse hypointensity in T2 FLAIR.
• CT scan shows similar features although better
highlights the lobulated quality of the lesion. It
also reveals ring-like structures most compatible
with cartilaginous matrix production.
Question 2
• What is the differential diagnosis of a destructive
expansile skull base lesion?
Answer
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Osteoma
Chordoma
Chondroma
Plasmacytoma
Ossifying and Non-Ossifying fibromas
Fibrous Histiocytoma
Chondrosarcoma
Chondroblastoma
Meningioma
Metastatic Lesions
Question 3
• The lesion was biopsied and submitted for intraoperative examination. The specimen was firm
and heavily mineralized, making the smear
difficult. Describe the findings. How would you
report to the surgeon?
• Click here to view the smear
Answer
• The smear shows a dense, cohesive, highly
cellular neoplasm that is extensively
mineralized. The cells appear large, with ovoid
nuclei and fine, evenly dispersed chromatin. The
cells are arranged in sheets and interweaving
streams. No mitotic activity is seen. Very rare
multinucleated giant cells are seen. Within the
background are moderate numbers of
inflammatory cells and extensive hemosiderin
deposition.
• A. Neoplastic
• B. Large spindle cells and giant cells seen
Question 4
• The specimen was then resected and submitted
for pathologic examination. It was heavily
mineralized and had to undergo decalcification
prior to processing.
• How would you describe the findings?
• Click here to view the H&E slide
Answer
• The tissue show a mildly polymorphic neoplasm
comprised predominantly of spindle cells with smaller
regions of epithelioid cells as well as multinucleate giant
cells. The majority of cells have round-to-ovoid nuclei
with evenly distributed chromatin, mildly irregular nuclear
contours and distinct nucleoli. Some cells show
hyperlobulated nuclei with prominent nuclear grooves.
No mitotic activity is seen. Many of the cells show
homogeneous amphiphilic-to-light eosinophilic
cytoplasm, with a lesser number displaying dense
eosinophilic cytoplasm. The tumor cells show infiltrative
and solid growth patterns. The majority of background
tissue consists of distinct appearing fibrillary and
mineralized osteo-chondroid matrix with multifocal
calcification. Some regions appear fibrous, with thickwalled sclerotic blood vessels scattered throughout.
Variably dense lymphoplasmacytic infiltrates are seen
throughout the lesion.
Question 5
• What is your differential diagnosis based on this
histology (abundant osteochondroid matrix
production)?
Answer
• Chondroblastoma
– Although chordoma, chondroma, and
chondrosarcoma are theoretically still in
the differential, the lack of physaliferous
cells (chordoma), well-differentiated
chondrocytes (chondroma) and
extensive mineralization and fibrosis
(not a consistent feature of any of these
entities) essentially excludes these as
diagnostic possibilities.
Question 6
• What immunohistochemical stains would you
order to confirm the diagnosis of
chondroblastoma?
Answer
• S100
• Vimentin
• Low molecular weight keratin, PAS with diastase
(glycogen)
• Reticulin (surrounds each cell)
• Neuron specific enolase (NSE)
• Click to see S100, NSE
Question 7
• The patient has a reported history of recurrent
chondroblastoma, which is now confirmed by
H&E and immunohistochemical examination.
• How aggressive are these tumors?
Answer
• Chondroblastomas usually behave in a benign
fashion, although local recurrence is common.
Sometimes they behave more aggressively,
invading surrounding tissues and in some cases
resulting in metastases. Metastases, however,
usually occur following surgical manipulation of
the primary lesion.
Question 8
• Is the skull base an unusual location for this
tumor?
Answer
• Yes. Most cases of chondroblastoma
occur in the distal femur, proximal
humerus, proximal tibia, and sometimes
the pelvis. Approximately 60 cases of skull
base chondroblastoma have been
reported worldwide.
Question 9
• Where do chondroblastomas most often
occur in the head?
Answer
• They most commonly occur in the
temporal bone.
Question 10
• What age group is most commonly
affected?
Answer
• Chondroblastomas of the lone bones are
almost exclusively found in patients
(usually males) in the second decade of
life. Skull base chondroblastomas are
almost exclusively found in patients over
the age of 30.
Question 11
• What cytogenetic abnormalities are
associated with chondroblastoma?
Answer
• Recurrent cytogenetic abnormalities on
chromosome 6 have been found.
• Recent studies have also shown LOH on
5q, 9p, 11p, 13q, and 19q.
• Loss of heterozygosity of 17p (p53) has
also been reported in greater than 50% of
chondroblastomas
References
• Kutz JW, Verma S, Tan H, Lo W, Slattery W, Friedman R. Surgical
Management of Skull Base Chondroblastoma (2007).
Laryngoscope. 117:848-853.
• Rosai J. Rosai and Ackerman’s Surgical Pathology, Ninth Edition
(2004). Elsevier, Inc.
• Blaauw G, Prick J and Versteege C. Chondroblastoma of the
temporal bone (1988). Neurosurgery, 22:1102–1107.
• Goga D, Fassio E, Fetissof F, Jan M. Chondroblastoma of the
temporomandibular region (1999). J Oral Maxillofac Surg. 57:12701272.
• Papachristou D, Goodman M, Cieply K, Hunt J, Rao U. Comparison
of allelic losses in chondroblastoma and primary chondrosarcoma of
bone and correlation with fluorescence in situ hybridization analysis
(2006). Hum Pathol. 37(7):890-898.