International Journal of Pediatric Otorhinolaryngology Extra
Volume 1, Issue 1 , Pages 36-40, March 2006

Postcricoid inflammatory myofibroblastic tumor (inflammatory pseudotumor) in a 10-year-old girl

Cleveland Clinic Foundation, Head and Neck Institute, 9500 Euclid Avenue, 44195 Cleveland, OH, USA

Received 1 October 2005; received in revised form 29 November 2005; accepted 6 December 2005.

Article Outline

Summary 

Inflammatory myofibroblastic tumor (IMT) is a benign spindle cell tumor of disputed nosology and unknown etiology that occasionally presents in the head and neck but is known to occur throughout the body in patients of all ages. IMT is identified by several alternative names in the literature; inflammatory pseudotumor and plasma cell granuloma are among the most prominent. We present a case of IMT arising in the postcricoid region of the hypopharynx in a 10-year-old girl and review the literature of IMT involving the head and neck. To the best of our knowledge, this is the first report of an IMT arising in this location. The patient was treated with endoscopic surgical excision and remains free of disease 2 years following the initial surgical resection. Histologically, the differential diagnosis of IMT includes both benign and malignant neoplasms, making frozen section interpretation challenging. Highlighting this is a case report wherein the presumptive frozen section diagnosis was interpreted as rhabdomyosarcoma, while permanent histology was consistent with IMT. Therefore, surgical decisions based purely on a frozen section diagnosis of malignancy may result in inappropriate and overly aggressive surgical treatment.

Keywords: Inflammatory myofibroblastic tumor, Inflammatory pseudotumor, Postcricoid hypopharynx, Children

 

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1. Introduction 

Inflammatory myofibroblastic tumor (IMT) was first described by Brunn in 1939. Bahadori and Liebow [1] published the first definitive case series of inflammatory myofibroblastic tumors of the lung in 1973, coining the term “plasma cell granuloma”. These tumors most commonly arise in the lungs and abdomen, but they have been reported in virtually all anatomic subsets of the body in patients of all ages [2]. In the head and neck, the orbit [2] is the most common site of occurrence, followed by the upper aerodigestive tract (nasopharynx, oropharynx, larynx, subglottis and trachea) [3], [4], [5], [6], [7], [8], [9], nasal cavity [10], [11], paranasal sinuses [12], temporal bone [13], [14], parapharyngeal space [15], [16], [17], pterygomaxillary space [18], thyroid [19] and epiglottis [20]. These tumors tend to be locally aggressive, benign tumors which may grow slowly or rapidly, usually manifesting with progressive symptoms referable to mass effect.

Many alternative names have been ascribed to this entity, including plasma cell granuloma, inflammatory myofibroblastic tumor, plasma cell pseudotumor, xanthomatous pseudotumor, pseudosarcomatous myofibroblastic proliferation and inflammatory myofibrohistiocytic proliferation. The multitude of names assigned to these tumors is a consequence of the variable forms in which the tumor may present. Some authors have proposed the name “inflammatory myofibroblastic tumor” as a proper descriptive term for this tumor, rather than the more vague “inflammatory pseudotumor.”

The etiology of IMT remains poorly defined, and several theories have been proposed in regards to the origin of this tumor, including infectious, reactive (post-surgical or foreign body) and immunologic etiologies [21]. It may be reasonable to assume, based on the diversity of presentation and suggested etiologies, that these tumors represent a family of neoplasms rather than a single clinical entity.

The histopathology of IMT varies, with some tumors having a myxoid stroma with loosely arranged cytologically bland spindled fibroblasts and myofibroblasts admixed with chronic inflammation, while other tumors have a fascicular growth pattern with an intense associated lymphoplasmacytic infiltrate. Cytologic atypia and atypical mitoses are not usually identified in IMT. However, there are rare anecdotal reports of histologic malignant transformation [22], [23]. In this patient's age group, the histologic differential diagnosis should include benign entities such as nodular fasciitis and malignant neoplasms such as Hodgkin's disease and spindle cell subtype of rhabdomyosarcoma. The diagnosis is difficult to determine based solely upon frozen section, therefore, final diagnosis is often deferred until permanent sections have been interpreted. The spindle cells exhibit diffuse cytoplasmic reactivity for vimentin and reactivity for smooth muscle actin and desmin, and muscle specific actin is identified in a majority of cases [23].

Surgical excision is considered the mainstay of treatment. Recurrence following complete surgical excision is rare. However, one report cited a recurrence rate of 8% for extrapulmonary inflammatory myofibroblastic tumors in children when confined to a single organ [24]. Other effective treatment modalities described in the literature include radiation therapy [10], corticosteroid therapy [25] or concomitant radiation and steroid therapy [26]. Prognosis is excellent.

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2. Case report 

A 10-year-old girl presented to the pediatric otolaryngology clinic with a 2-year history of progressive dyspnea and stridor with exertion, worse when supine. Her symptoms had progressed to the point to where she had significant difficulty breathing during sleep as reported by her mother. She did not report any swallowing difficulties. The patient's past medical history was significant only for a tonsillectomy and adenoidectomy (for recurrent streptococcus infections) at the age of 3. She was well-nourished and did not report a history of weight loss or any other constitutional symptoms.

Physical exam findings included a mildly hoarse voice and minimal stridor at rest. She exhibited severe inspiratory stridor with exertion (climbing two flights of stairs). Flexible fiberoptic nasolaryngoscopy in the office revealed a significantly narrowed supraglottic larynx with a curled epiglottis and significant shortening of the aryepiglottic folds. The true vocal cords were not visualized due to the supraglottic narrowing. The neck was supple without masses or lymphadenopathy.

The patient was subsequently taken to the OR for microlaryngoscopy and bronchoscopy. This revealed a firm, 1.5cm submucosal mass in the midline of the postcricoid region of the hypopharynx (Fig. 1). The mucosa overlying the mass appeared normal. The epiglottis was curled upon itself and the aryepiglottic folds appeared scarred and significantly shortened, resulting in significant narrowing of the supraglottic airway which worsened with dynamic inspiration. The remainder of the upper airway appeared normal. Biopsies of the mass were taken using cup forceps. Final pathology was consistent with chronic inflammation and fibrosis.

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  • Fig. 1. 

    Direct laryngoscopy revealed a thickened postcricoid hypopharynx with shortened aryepiglottic folds and a curled epiglottis resulting in significant narrowing of the supraglottic airway.

A contrast-enhanced CT of the neck was obtained which revealed a 1.5cm×1.2cm mass centered in the postcricoid region of the hypopharynx involving both aryepiglottic folds which exhibited intense, diffuse heterogeneous enhancement following contrast administration (Fig. 2). An MRI of the neck also revealed a 1.5cm mass in the postcricoid region of the hypopharynx with increased signal intensity on T2 weighted images and diffuse, heterogeneous enhancement following gadolinium administration. These findings raised suspicion for malignancy and a CT of the head and chest as well as CXR showed no evidence of metastatic disease.

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  • Fig. 2. 

    Post-contrast axial CT scan of the neck showing a 1.5cm×1.2cm mass in the postcricoid region of the hypopharynx exhihibiting intense, heterogeneous contrast enhancement.

The patient was taken back to the OR and a direct laryngoscopy with transoral excisional biopsy in conjunction with incision of the foreshortened aryepiglottic folds was performed. The initial frozen section was interpreted as chronic inflammation and fibrosis. Permanent section pathology (Fig. 3A and B) revealed a cytologically benign-appearing proliferation of stellate and spindle-shaped cells arranged in a vague fascicular architecture with an accompanying prominent lymphoplasmacytic infiltrate. The cytoplasm of a majority of the spindle cells had immunoreactivity for smooth muscle actin (Fig. 3C). This constellation of histologic and immunophenotypic findings is consistent with the diagnosis of IMT.

  • View full-size image.
  • Fig. 3. 

    (A and B) Fascicular growth pattern of bland spindle and stellate-shaped cells with an admixed prominent lymphoplasmactyic infiltrate (hematoxylin and eosin stain, 200× and 400×); (C) immunohistochemical staining revealing diffuse cytoplasmic reactivity for smooth muscle actin within the spindle cells (200×).

The patient returned to the OR a third time for a repeat direct laryngoscopy with biopsies of the postcricoid hypopharynx and aryepiglottic folds in order to ensure negative margins. All margins were subsequently negative on permanent section. The patient underwent examination under anesthesia 3 months following the initial resection. Her airway remained widely patent and there was no evidence of recurrent tumor (Fig. 4). Biopsies of the postcricoid hypopharynx at the site of the previous resection were consistent with granulation tissue. The patient remains symptom-free 2 years following the initial resection. Her voice is normal and she is swallowing normally.

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3. Discussion 

Inflammatory myofibroblastic tumors are benign neoplasms of unknown etiology that most commonly arise in the lungs but have also been reported in virtually anatomic subsets of the upper aerodigestive tract. To the best of our knowledge, this is the first report of an IMT arising in the postcricoid region of the hypopharynx. Several reports of IMT of the larynx have been made; these usually arise from the true vocal cords or pyriform sinuses [3]. The progressive 2-year history of inspiratory stridor and dyspnea with exertion in this patient is consistent with the slow, indolent growth pattern seen in many of these tumors. Given that the direction of growth of the tumor was more anterior than posterior, the presenting symptoms in this patient were referable to the upper airway as opposed to dysphagia. Complete endoscopic surgical excision in this case resulted in cure without any functional deficits. We encourage the otolaryngologic surgeon to act with caution whenever encountered with a spindle cell tumor of the head and neck, especially those tumors with an indolent growth pattern. Frozen section interpretation of IMT can be problematic, as both malignant neoplasms and benign reactive processes are within the differential diagnosis. A report in the literature describes a presumptive frozen section diagnosis mistakenly interpreted as rhabdomyosarcoma, while permanent histology was consistent with IMT [27]. Any surgical decisions based purely on this improper diagnosis may result in inappropriate and overly aggressive surgical treatment (in this case, a total laryngectomy in a 10-year-old girl).

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4. Conclusion 

IMT is a benign neoplasm occasionally encountered in the upper aerodigestive system. The otolaryngologic surgeon should keep this diagnosis in the differential for any spindle cell tumor of the head and neck. Frozen section diagnosis is usually inconclusive, therefore, an accurate permanent section diagnosis is essential in order to avoid overly aggressive surgery. Surgical excision is the preferred treatment and very few reports of recurrence following excision have been reported. Prognosis is excellent following complete surgical excision.

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References 

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PII: S1871-4048(05)00014-6

doi:10.1016/j.pedex.2005.12.001

International Journal of Pediatric Otorhinolaryngology Extra
Volume 1, Issue 1 , Pages 36-40, March 2006

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