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The Hidden Giant: A Deep Dive Beyond The Back-Bone
Case Study
Thu Jun 06 2024
CLINICAL DETAILS :-
A 33 years female presented with low backache radiating to the left from 6 months aggravated since 2 weeks. She was initially evaluated with CT lumbar spine followed by MRI pelvis.
IMAGING FINDINGS :-
A well-defined, heterogeneously hypo enhancing lesion with multiple ring and arc calcification, in the presacral space. No obvious fat within. Cauliflower-like bony spiculations and thick periosteal reactions are seen in the anterior surface of sacral vertebral bodies ( S1 and S2 ). There is extension of soft tissue extension into the left side S1-S2 neural foramina with widening. Thoracic and abdomen imaging revealed no other lesions.
MRI pelvis was done for the further characterization of lesion.
It was heterogeneously hyperintense on T2 with predominantly peripheral enhancement on post contrast sequence. T1 and T2 irregular hypointense spiculations in the central region along the anterior surface of sacral vertebral bodies which was blooming on FFE corresponds to bony spiculations on CT. Altered signal intensity in the S1 and S2 vertebral body and left sacral ala.
IMAGING IMPRESSION :-
Presacral mass with chondroid matrix and periosteal reaction, likely periosteal chondrosarcoma.
Biopsy was done and histopathology revealed extensive necrosis with cartilaginous components.
DIFFERENTIAL DIAGNOSIS :-
Periosteal chondroma - a mildly destructive tumour originating in the posterior neural arch of the spine and containing stippled calcification suggests the diagnosis of periosteal chondroma. Computed tomography shows a soft-tissue mass of iso or high density, containing stippled calcifications and local bone destruction. Lesion is usually <3 cm and occurs in young people.
Periosteal osteosarcomas - Predominantly chondroblastic osteosarcoma with a chondroid matrix. Hyperintense on T2 with strands of ossification within the lesion perpendicular radiating from the surface and more pronounced towards the cortex. Periosteal osteosarcomas are seen in a wide age range from the first to the seventh decade with a peak in the second decade of life.
Giant cell tumor - Lytic, expansile, often eccentrically located, vascular with substantial enhancement. Tends to occur in the 2nd–4th decades and is more common in women.
Neurofibroma - Target appearance on T2W images (central area of low SI with a high-SI rim), low attenuation at CT.
Schwannoma - Remodeling or erosion through sacral bone, heterogeneous mass with thin pseudocapsule and small cystic areas. These tumors have a male predominance and generally present in the third–fifth decade.
Chordoma - Destructive lytic lesion, large presacral soft-tissue component, high SI on T2W images.
DISCUSSION :-
Periosteal chondrosarcomas, previously also known as juxta-cortical chondrosarcomas, are cartilaginous or chondroid matrix-generating neoplasms originating in close association with the periosteum from the bony surface.
While mostly seen in the thoracic spine, sacral involvement is rarely seen.
Presents commonly in adults between the 3rd and 4th decade of life with a slight male predilection and clinical symptoms are nonspecific, including swelling, painless or painful mass.
Due to the nonspecific presentation, radiological findings represent a crucial role to differentiate periosteal chondrosarcoma from other surface tumors as the correct treatment with wide surgical resection provides an excellent prognosis.
As MRI has a higher performance to evaluate bone marrow and soft tissues it is superior to all the other imaging methods to characterize the tumor.
The lesion normally presents on MRI as a soft tissue mass ascending from the surface of the bone with an intermediate to low intensity on T1-weighted sequences and a lobulated high-signal on T2-weighted sequences. Peripheral and septal enhancement occurs after intravenous contrast administration.
CT is ideal to identify calcifications that characterize the cartilage matrix and to evaluate cortical changes and periosteal reaction. Characteristic features of the chondroid matrix are “dense”, “stippled” or “rings and arcs”.
Periosteal chondrosarcomas are identical histologically and radiologically to other surface tumors and periosteal chondroma may be the most difficult to distinguish as both tumors contain cartilage. Therefore, certain imaging features such as the size of the lesion and cortical invasion are essential for differential diagnosis.
Considering that periosteal and parosteal osteosarcomas histologically also demonstrate chondroid matrix mineralization must be included in the differential diagnosis, although those lesions present osteoid matrix and bone tumoral formation.
In conclusion, periosteal chondrosarcoma is a rare primary low-grade surface bone tumor. Radiologists must be aware of the imaging aspects and differential diagnosis which is crucial for clinical management and prognosis depending on the appropriate surgical excision.
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Case Study
An Indian Spring - Unrest in the Chest
A 57 year old lady presented with a left chest wall nodule with a 3 week history. There was no other contributory history. This was a referral from an interventional radiologist and a core biopsy was submitted for histopathologic analysis. The radiologist’ impression included a soft tissue tumour and a hemato-lymphoid malignancy. No whole body imaging was available at the time.
The biopsy indicated a high grade, poorly differentiated large cell malignancy (pending immunohistochemical characterisation). Lesional tumor cells were set in a syncytial growth pattern with a streaming pattern seen focally, and found infiltrating between muscle bundles of the chest wall. Significant tumor emperipolesis was recorded.
Basis the morphology, a hemato-lymphoid malignancy was favoured over a soft tissue tumor. We circled back to the radiologist inquiring about the presence of multiple lymph nodes and/or lymph nodal masses or hepatosplenomegaly, if any. Whole body imaging was then ordered and lo and behold there was multiple lymphadenopathy found including, in the mediastinum together with bilateral renal enlargement present.
Stop press: in light of new radiologic findings coming to the fore, and presence of significant tumor emperipolesis as morphologic finding, our thoughts also turned to ‘biphasic squamoid’ papillary renal cell carcinoma (BPRCC) where emperipolesis is now accepted as a constant feature. However, in the present clinical context of chest wall nodule with multiple nodes in mediastinum and bilateral renal involvement, this was mooted as a remote possibility.
Immunostains were ordered for lymphoma work up and tumor cells were found reactive for CD45, CD20, CD30 and negative for T cell marker, CD43 as well as for ALK1. Cut to the chase, we now had a diagnosis favouring CD30 + anaplastic variant of DLBCL rather than a lymphocyte depleted Hodgkin disease which is the closest differential on immunohistology; absent a mixed inflammatory infiltrate and diffuse CD30 reactivity in the given case.

Next, a Hans algorithm was employed using CD10, bcl-6 and MUM1 to broadly stratify the DLBCL into two molecular prognostic groups: Germinal centre B cell (GCB) and activated B cell/ non GCB subtype. Note the GCB subtype has a better prognosis than the non GCB subtype. Our case yielded a CD10 — bcl 6 + and MUM1 + phenotype indicating a non GCB subtype and it follows therefore; a worse prognosis. Further and more, the International Prognostic index (IPI) lends itself handy as a clinical tool for predicting overall and progression free survival in DLBCL- something which is outside the scope of the current discussion.
No conversation on the DLBCL universe is ever complete without a refrain on ‘double hit’ and ‘triple hit status’ of the lymphoma. The double hit and triple hit status of DLBCL implies genetic rearrangement and/ or translocation of c- myc, bcl-2 or bcl-6 resulting in protein overexpression of these proteins (positive cut offs being defined at 70% of cells for c-myc and bcl-6 and 40% for bcl-2). Although protein expression by IHC is not a surrogate for cytogenetic testing, protein overexpression for c- myc, bcl-6 and bcl-2 can reliably indicate likely probability of double hit and triple hit status of lymphoma. Both double hit (DL) and triple hit lymphomas (TL) portend worse prognosis with poor response to chemotherapy and higher recurrence rates. In this instance, probability of a double hit lymphoma was considered less likely as c-myc and bcl2 proteins were not overexpressed in our case.
The final diagnosis offered was CD 30+ anaplastic variant of DLBCL, extranodal.
The received wisdom on testing for DL and TL status is that samples must be subjected for cytogenetic FISH based testing as it is more reliable and specific for these targets, and the same is incorporated into routine clinical practice.
As is wont to happen in non hospital based settings, the patient was referred to a tertiary care referral centre and lost to follow up.
To sum up, here we have an unusual extranodal presentation of a DLBCL (note extranodal DLBCLs are generally confined to gastrointestinal, skin, soft tissue, bone and genitourinary tract) wherein we are able to achieve prognostic stratification into two broad molecular subgroups on a targeted image assisted biopsy, enabling a ‘less is more’ approach to tumor diagnosis and prognosis with minimally invasive techniques of tissue sampling.

Case Study
The Carotid Conundrum: Unraveling Splaying- A Comprehensive Guide To Carotid Space Lesions
CLINICAL DETAILS
A 44-year-old female presents with a history of multiple episodes of giddiness. The patient reports noticing swelling within her oral cavity, specifically in the area posterior to the right tonsillar pillar for 6 months. On clinical examination, there is no palpable swelling in the neck. However, a significant parapharyngeal swelling, approximately 4x4 cm in size, is observed in the oral cavity posterior to the right tonsillar pillar. This swelling is associated with a deviation of the uvula to the left. The clinical findings suggest a possible mass or lesion in the parapharyngeal space, warranting further investigation to determine the underlying aetiology.

IMAGING FINDINGS:
MRI reveals a well-defined, oval-shaped lesion in the right carotid space, measuring 3x4x5 cm. The lesion causes splaying of the internal and external carotid arteries and extends medially into the right parapharyngeal space. The lesion is iso to hyperintense on T1/T2WI and shows homogeneous postcontrast enhancement.
CT angiography of neck and brain showed the above-mentioned lesion to be hypoenhancing in the arterial phase.
The differential diagnoses considered were carotid body tumour, cervical sympathetic chain schwannoma and vagal schwannoma. Vagal schschwannomas displace the carotid arteries anteriorly rather than splaying them. Cervical sympathetic chain schwannomas displace the carotid arteries anteriorly but occasionally splay the internal and external carotid arteries without encasement. Carotid body tumours are usually pulsatile in nature, show multiple internal flow voids, splay and encase the carotid arteries, and show intense early enhancement followed by rapid washout. However, in our case, the mass showed progressive enhancement. Hence, in the given clinical setting and after reviewing the radiological features, a probable diagnosis of schwannoma was made.
FOLLOW-UP
Patient underwent surgery and it was found to be arising from the hypoglossal nerve and the biopsy revealed schwannoma.
DISCUSSION
Here are the possible causes of Lyre sign and the imaging features:

CONCLUSION
The ‘Lyre’ sign describes the characteristic splaying of the carotid artery bifurcation due to a carotid body tumour on conventional carotid angiography. This sign, however, is not diagnostic of carotid body tumours. An accurate diagnosis is, therefore, essential before embarking on invasive procedures such as biopsy or aspiration to prevent potential catastrophe.
As this case exemplifies, the road to a definitive diagnosis demands a synthesis of clinical acumen, imaging finesse, and sometimes, surgical intervention.
Bottomline: “Not all that splays is carotid body tumor”!!
Dr Adarsh Ishwar Hegde
KH site, Manipal

Case Study
The Fine Line: Pelvic Pitfalls: Deceptive Findings in Pelvic Ultrasound
Dr Praveen Shastry – Head of Technical and Clinical Academics, KH, Manipal.
Ultrasonography is undeniably one of the most powerful tools in modern diagnostic imaging, with its ability to provide real-time, dynamic views of soft tissues and organs. However, the effectiveness of an ultrasound scan hinges on more than just the technology—it’s the expertise and discernment of the radiologist that bring each image to life.
Achieving the right diagnosis with ultrasound depends on many factors: the quality of the equipment, patient cooperation, optimal bladder filling, minimal intestinal gas, and, of course, a vigilant and adaptable mindset from the operator.
Pelvic imaging is a realm where even the most seasoned radiologists can encounter surprising pitfalls, with structures that often imitate each other in unpredictable ways. This case series delves into common but deceptively tricky situations where a fleeting glance might lead to misinterpretation. Here, we aim to bring clarity to those subtle yet significant differences that distinguish one diagnosis from another.
Case 1:
Clinical History: A 32-year-old woman with a history of abdominal bloating and mild pelvic discomfort and menstrual irregularities presents for an ultrasound. The patient complains of intense urge to micturate and is also associated urinary frequency, denies any pain / burning sensation during urination.
Initial Ultrasound Appearance: Urinary bladder was completely distended showing no calculi within. Uterus visualized normal. One ovary visualized normal. Other ovary could not be distinctly visualized – The report was generated based on what was seen!
Twist in the tale: Follow up was requested by the referring clinician (Secondary to mild increase in discomfort) - Large midline structure was actually a pelvic cyst that initially masqueraded as a full bladder.
Conclusion: While this structure was mistaken for a bladder due to its midline location and symmetry, the absence of squarish margins, well-defined edges gave away the true identity. Absence of ureteric jet is another indicator in this instance.
Take-Home Punchline: "When in doubt, wait for the stream—it’s the bladder’s signature move!"
Case 2: The Gaslighted Ovary
Clinical History: A 32-year-old woman presents with lower abdominal pain and intermittent bloating. She’s had irregular cycles but no other significant symptoms.
Initial Ultrasound Appearance: A suspicious hyperechoic focus found adjacent to the left ovary resulting in scattered bright echoes. The report was issued – stating that there is excessive bowel gas.
Final Diagnosis: Ovarian teratoma (dermoid), with mixed echogenic components, including fat and calcifications, that mimicked gas.
Conclusion: Teratomas or dermoids, often contain odd tissue components, including fat, hair, and even bone, which produce confusing echoes similar to gas. Recognizing these unusual reflections can avoid misdiagnosis.
Take-Home Punchline: "Not all bubbles pop! When shadowing lingers, think teratoma."
Case 3: The Sneaky Salpinx
Clinical History: A 41-year-old woman with chronic pelvic pain and recent worsening discomfort visits the clinic. She has a history of pelvic infections but no surgical history.
Initial Ultrasound Appearance: Multiloculated cystic structure alongside the uterus- showing incomplete internal septations. Resembling a cyst, yet doesn’t fully match the typical round ovarian cyst shape.
Final Diagnosis: Hydrosalpinx, a fluid-filled, dilated fallopian tube.
Conclusion: The “cogwheel” sign from mucosal folds in hydrosalpinx can be mistaken for cysts. Its tubular shape and the absence of typical ovarian structures confirmed its true identity. The buzz word is incomplete internal septations!!!!
Take-Home Punchline: "Don’t get twisted—if it’s tubular with incomplete septae- think hydrosalpinx, not a cyst!"
Case 4: The Cyst that Cried Wolf
Clinical History: A 28-year-old woman with acute onset of sharp pelvic pain arrives in the emergency department. Her last menstrual period was two weeks ago, and she’s had no recent health changes.
Initial Ultrasound Appearance: A complex, echogenic structure appears within the ovary. It’s difficult to discern whether it’s a solid mass or a hemorrhagic cyst, as it contains both solid-looking regions and some cystic fluid.
Differentials: Solid adnexal mass, hemorrhagic ovarian cyst, or endometrioma.
Final Diagnosis: Hemorrhagic cyst, verified through repeat imaging as the appearance slowly resolved.
Conclusion: While hemorrhagic cysts can initially appear complex and solid-like, they typically resolve on follow-up, unlike true solid masses. Let time and patient stability guide management.
Take-Home Punchline: "If it’s complex and confusing, give it time—a tumor won’t back down."
Case 5: The Torsion Illusion
Clinical History: A 23-year-old woman with severe, sudden-onset right-sided pelvic pain presents to the emergency room. She’s nauseous, and painkillers have offered minimal relief.
Initial Ultrasound Appearance: The right ovary appears enlarged with a slightly irregular outline, though some blood flow is still detected on Doppler, raising doubts about torsion.
Final Diagnosis: Ovarian torsion confirmed intraoperatively despite preserved Doppler flow.
Conclusion: Ovarian torsion can sometimes retain blood flow due to dual blood supplies. When clinical signs point toward torsion, follow through, as Doppler alone may mislead.
Take-Home Punchline: “Flow isn’t everything! Look deeper—torsion’s a twisty foe.”
This collection of cases highlights some of the most misleading situations in pelvic ultrasound and provides memorable takeaways that are both practical and engaging.
By staying receptive to different possibilities, they avoid jumping to conclusions and instead build a nuanced, patient-centered diagnosis. In the world of ultrasound, it’s not just about seeing—it’s about seeing beyond.