A 50-year-old post-menopausal female presented to the orthopaedic department with an inability to bear weight on her right leg following a trivial fall. Her past medical history was significant for a neck swelling for the last 20 years which was being treated by indigenous ayurvedic medicines. Otherwise, her medical, gynaecological and surgical history was unremarkable.
Radiograph of the right thigh revealed a lytic lesion in the subtrochanteric region with a displaced pathological fracture. Bone fragments were seen in the adjacent soft tissue. The mineralisation of skeleton appeared normal for age and sex [Figure 1a].
Screening chest radiograph revealed a soft tissue density lesion compressing and displacing the trachea towards the right. Bilateral lung fields and cardiac shadow were unremarkable [Figure 1b].
Contrast-enhanced CT of chest and abdomen was performed for identification of a primary lesion and metastatic workup which demonstrated a heterogeneously enhancing mass completely replacing both lobes of thyroid with few chunky calcifications, displacing the oesophagus and trachea to right, focally abutting the left CCA & brachiocephalic vein with its luminal attenuation. No significant lymphadenopathy was seen. Sections of the lung demonstrated few randomly distributed soft tissue nodules on a background of chronic infective changes. Lower sections of pelvis also demonstrated the pathological fracture with soft tissue within [Figure 2].
Papillary carcinoma of thyroid is the most common thyroid malignancy followed by follicular carcinoma. A major difference between the two is higher hematogenous spread of malignancy in the latter . In a female patient presenting with pathological fracture, breast carcinoma tops the list of differential diagnosis followed by thyroid malignancies .
The usual clinical presentation of differentiated thyroid cancer is a thyroid mass but presentation as a pathological fracture may be seen in up to 38-62% cases [3,4]. The axial skeleton accounts for the more common site of bone metastasis with isolated appendicular skeletal metastasis being a rarer occurrence. Presentation with pathological fracture warrants imaging for identifying the primary lesion as well as for metastatic workup. Considering the age and sex of our patient, breast and thyroid malignancy were the top two differentials which were assessed by clinical examination and then imaging.
Awareness about features of a pathological fracture is necessary to point the clinician in the correct direction and fasten the diagnostic process of already advanced malignancy. Presence of a lytic lesion, a horizontal fracture line and enhancing soft tissue within the broken cortex on cross-section imaging are the pointers to a metastatic pathological fracture.
Diagnosis relies on biopsy from the lesion which can be taken either during fixation or under image guidance.
In our case, the thyroid lesion appeared aggressive on imaging with no evidence of mass in either breast and thus, was the imaging diagnosis for the possible primary lesion which was then confirmed following a bone biopsy from the fracture site and FNAC from the thyroid lesion.
Radiotherapy with surgical fixation of the pathological fracture and concurrent bisphosphonate therapy was offered to the patient.
Take-Home Message / Teaching Points
Vigilance about features of a pathological fracture is important along with awareness about the most prevalent possible primary lesions presenting as bone metastasis to begin a thorough search in the correct direction and reach the diagnosis for early intervention and treatment.
Written informed patient consent for publication has been obtained
 Pittas AG, Adleer M, Fazzari M, Tickoo S, Rosai J, Larson SM, et al. . Bone metastases from thyroid carcinoma: clinical characteristics and prognostic variables in one hundred forty-six patients. Thyroid 2000;10:261–8.
 Rougraff BT. Evaluation of the patient with carcinoma of unknown origin metastatic to bone. Clin Orthop 2003;415:S105–9.
 Kallel F, Hamza F, Charfeddine S, Amouri W, Jardak I, Ghorbel A, et al. Clinical features of bone metastasis for differentiated thyroid carcinoma: A study of 21 patients from a Tunisian center. Indian J Endocrinol Metab. 2014 Mar;18(2):185–90.
 Bernier MO, Leenhardt L, Hoang C, Aurengo A, Mary J, Menegaux F, et al. Survival and therapeutic modalities in patients with bone metastases of differentiated thyroid carcinomas. J Clin Endocrinol Metab 2001 Apr;86(4):1568–73.
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