Inflammatory carotid pseudotumor: case report and review of the literature

Introduction

The differential diagnosis of a solitary mass in the region of the carotid triangle includes carotid body tumor, aneurysm and arterial rupture with hematoma formation. Inflammatory pseudotumor is an extremely rare condition; involvement of the carotid without involvement of other sites in the head and neck is rarely reported (Table 1)^1–8.

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Table 1

Review of additional cases reported in the literature

Sl no.	Author	No. ofpatients	Presentingsymptoms	Treatment	Outcome
1	De Vuysere et al. 1	3	Mass, stenosis	Resection, steroids	Resolution of symptoms, no recurrence at 2.5 years
2	Lee et al. 2	2	Mass	Resection steroids	Resolution of symptoms
3	Farage et al. 3	1	Mass, carotidynia	Steroids	Resolution of symptoms, no recurrence at 1 year
4	Ceruse et al. 4	1	Mass	Resection steroids	Resolution
5	Ding et al. 5	1	Mass	Not mentioned	Not mentioned
6	Park et al. 6	2	Mass	Not mentioned	Not mentioned
7	Kim et al. 7	2	Mass	Resection, steroids	Resolution
8	Okamoto et al. 8	1	Mass	Resection	Resolution

Case history

A 48-year-old man presented with a painless gradually progressive mass in the left upper neck for five months. He also complained of headache and vertigo with blurring of vision. He had been diagnosed to have a sick sinus syndrome and was on a cardiac pacemaker. He did not have any other complaints on systems review. On examination there was a 4 × 4 cm non-tender, non-pulsatile left carotid triangle mass. There was no palpable adenopathy. The cranial nerves, oropharynx and larynx were normal. Other systems examination was normal. On investigation, chest X-ray, cell counts and inflammatory markers in blood were normal. He had undergone an open biopsy of the neck mass elsewhere, which was reported as fibroadipose tissue. Computed tomography angiogram revealed a circumferential non-enhancing mass around the left common carotid artery with no luminal narrowing (Figure 1a). Oral cavity, nasopharynx and orbits were normal. OPEN IN VIEWER

The patient was referred with differentials of paraganglioma or carotid lymphoma. The upper neck was scarred from previous surgery, clinical features and imaging were in favor of lymphoma, and fine needle aspiration cytology (FNAC) was performed to avoid repeat open biopsy. However, ultrasound-guided FNAC was non diagnostic, excision biopsy was performed. Intraoperatively, there was an adherent fibrous mass around the left carotid. The tumor was shaved off the carotid artery as the distal internal carotid also appeared infiltrated. The frozen section showed lymphoid tissue with no evidence of malignancy. However, the final histopathology was reported as inflammatory pseudotumor (Figures 2a and b). Steroids were not prescribed in the immediate postoperative period as near-total excision was done. Recovery was uneventful. The patient presented with recurrence of symptoms and a larger swelling after eight months (Figure 1b). Repeat blood tests were normal. The patient was started on 1 mg/kg steroids (tab. prednisolone) for a week followed by a tapering dose over a month. The swelling reduced completely in a week, there was no recurrence after three months of stopping steroids (Figure 1c). The patient did not have a clinical recurrence till date (2 years postsurgery). OPEN IN VIEWER

Discussion

Carotid inflammatory pseudotumor is very rare.^1–8 It presents as unilateral neck swelling, radiographic presentation includes a mass encasing the carotid bifurcation with no increased vascularity (Table 1). Vessel narrowing may be seen. It can be present with involvement of other head and neck sites. On magnetic resonance imaging the mass has a relatively low T2-signal. Histopathologically, a variety of patterns may be found in the same tumor; some composed predominantly of bland spindle-shaped cells loosely arranged in myxoid and hyaline stroma with scattered inflammatory cells; others are composed of a compact proliferation of spindle-shaped cells arranged in storiform growth pattern usually associated with prominent lymphoplasmacytic infiltrate, occasionally with formation of germinal centers. The diagnosis is sometimes only established postoperatively;^1–3 the frozen section did not reveal the diagnosis in our patient. This is a benign process but it can mimic malignancy and can recur. Though spontaneous regression of pseudotumor of the urinary bladder has been reported, no such regression has been reported in carotid tumors. Tumors have been treated by radical surgery, steroids, radiotherapy and immunosuppression. Response to steroid treatment appears to be the best, various drug regimens are used with similar outcomes. Though data on steroid therapy are limited, use as part of the initial treatment plan may help in avoiding recurrence.^1–4,7 It should be used postoperatively as an adjunct.

Radiation and immunosuppression are reserved for patients with non-resectable tumors not responding to steroids.

Though remission after surgical excision of inflammatory carotid pseudotumor has been reported, in our case, the tumor recurred. Prescribing a course of steroids for patients with this condition may help in averting surgery and avoid tumor recurrence.