Journal of Cancer Research and Therapeutics Medknow Publications on behalf of the Association of Radiation Oncologists of India (AROI) ISSN: 0973-1482 EISSN: 1998-4138 Vol. 6, Num. 3, 2010, pp. 321-323

Journal of Cancer Research and Therapeutics, Vol. 6, No. 3, July-September, 2010, pp. 321-323

Case Report

Unresectable basaloid squamous cell carcinoma of the trachea treated with concurrent chemoradiotherapy: A case report with review of literature

Nikhil P Joshi¹, Kunhi Parambath Haresh¹, Prasenjit Das², Rajender Kumar³, Ramachandran Prabhakar¹, Daya Nand Sharma¹, Puthiyeduthu Heera¹, Pramod Kumar Julka¹, Goura Kishor Rath¹

¹ Department of Radiotherapy and Oncology, All India Institute of Medical Sciences, New Delhi, India
² Department of Pathology, All India Institute of Medical Sciences, New Delhi, India
³ Department of Nuclear Medicine, All India Institute of Medical Sciences, New Delhi, India

Correspondence Address:Kunhi Parambath Haresh, Department of Radiotherapy and Oncology, All India Institute of Medical Sciences, New Delhi- 110 029, India, kpharesh@rediffmail.com

Code Number: cr10074

PMID: 21119264

DOI: 10.4103/0973-1482.73341

Abstract

Keywords: Basaloid squamous cell carcinoma, chemoradiation, PET based radiotherapy planning, tracheal tumors

Introduction

Malignant tracheal tumors are rare malignancies with preponderance for males. ^[1] The most common histology for a primary tracheal tumor is squamous cell carcinoma. Basaloid carcinoma is an uncommon variant of this squamous cell carcinoma of the trachea. The second most common histology is adenoid cystic carcinoma (ACC). ^[2],[3] The pathological recognition of basaloid squamous cell carcinoma and its distinction from adenoid cystic carcinoma of the trachea is important for its management.

Case Report

A 50-year-old man was referred to us for complaints of dyspnea on exertion and hoarseness since seven months. He also had dysphagia since the last three months. He has a 45 pack-year history of smoking and an equally long alcohol intake. His physical examination was unremarkable except for mild stridor on a background of scattered crepitations possibly secondary to a lower respiratory tract infection. He was initially seen at the department of thoracic surgery. After a normal chest X-ray, he was taken up for bronchoscopy which revealed a circumferential infiltrative growth extending from 1 cm below the true vocal cords up to the carina and it was bleeding on contact. A contrast enhanced CT scan of the chest and upper abdomen revealed a 4.7 × 3.6 × 2.5 cm soft tissue mass along the left lateral wall of the trachea extending a centimeter below the true vocal cord up to 1 cm above the carina. The tumor was extending into the paratracheal fat. A few enhancing left paratracheal and aorticopulmonary lymph nodes were noted, the largest being 1.3 × 1cm. PET CT done confirmed the findings [Figure - 1]. An upper GI endoscopy done was normal. The patient underwent a debulking of his tracheal growth; 90% of the tracheal lumen was relieved. The histopathology revealed basaloid carcinoma of the salivary gland type [Figure - 2].

After reviewing the case, this patient was deemed unresectable and referred to us. He was subsequently planned for a course of definitive chemoradiation. We electively placed a nasogastric tube before starting treatment to facilitate feeding and avoid trauma to the esophagus by food during treatment in view of the locally advanced nature of the tracheal disease.

The patient was immobilized using a custom made thoracic thermoplastic cast (Orifit ^TM ). PET CT simulation was done in the treatment position. The data set was subsequently transferred to our Eclipse ^TM treatment planning system. The patient was planned for three dimensional conformal radiation delivery using left, right anterior oblique beams and a direct anterior beam to deliver an initial dose of 45 Gy in 25 fractions followed by a boost of 15 Gy in 8 fractions by left and right oblique beams. We decided to give him concurrent chemotherapy with weekly paclitaxel 50 mg per meter square and carboplatin (AUC = 2).

The patient completed his prescribed course of chemoradiotherapy of 60 Gy in 33 fractions and seven doses of weekly paclitaxel and carboplatin without any major complications. Apart from grade two esophageal reaction (CTCAE Version 3) during the third week of therapy which was managed conservatively, his treatment course was largely uneventful. At the end of treatment, he was more or less free of dyspnea and his hoarseness improved.

The nasogastric tube was removed two weeks after treatment completion and the patient was able to take about 2 l of liquids and semisolids a day. PET CT done two year post treatment revealed no evidence of local or systemic disease [Figure - 3]. At third year of follow up, he developed multiple bone and lung metastases and he is being treated by palliative chemotherapy with paclitaxel and carboplatin.

Discussion

Basaloid squamous cell carcinoma is an aggressive, high grade tumor with a tendency to be multifocal, deeply invasive and metastatic. It metastasizes via lymphatics and blood vessels to regional and distant lymph nodes, lung, bone, skin and brain. ^[4] Adenoid cystic carcinoma of the trachea on the other hand has much less aggressive potential. ^[3]

Saltarelli et al. were the first to report a primary basaloid squamous cell carcinoma arising from the trachea. ^[4] The first case was a 52-year-old lady with 4.5 cm tracheal mass located 3.5 cm above the carina. Her disease was localized to the trachea. She underwent partial tracheal resection and post operative radiation therapy. She was reported to be well six months after her treatment. The second case was that of a 75-year-old man who presented with aspiration pneumonia and later died of pulmonary complications. The autopsy revealed a large tracheal neoplasm eroding into the esophagus causing a fistula. No metastases were apparent. ^[4] A third case of primary basaloid squamous cell carcinoma of the trachea is described in a 48-year-old man. This patient had a two year history of hemoptysis. Eventually his tracheal tumor was debulked by bronchoscopy. His disease was localized to the trachea and he subsequently underwent definitive resection with negative margins. No radiotherapy was administered. Within four months of surgery, he developed metastasis in the lumbar spine. ^[5]

Basaloid squamous cell carcinoma of the trachea is a rather aggressive tumor generally associated with a rapidly fatal course. ^[4] Considering basaloid squamous cell carcinomas of the upper aerodigestive tract, these are considered high grade malignancies, with 68% having regional metastases at the time of presentation. ^[1]

The histopathological hallmark of a basaloid squamous cell carcinoma (BSCC) is that in addition to the conventional malignant squamous cell islands, there are many islands of primitive undifferentiated basaloid cells with hyperchromatic nuclei and high nuclear-cytoplasmic ratio along with frequent primitive glandular structures. Peripheral pallisading around the basaloid islands and deposition of variable amount of basement membrane material is characteristic. ^[1] Immunophenotypically, this tumor shows peripheral positivity for high molecular weight cytokeratins 14, 18 and 19, epithelial membrane antigen and also show variable positivity for vimentin and neuroendocrine markers. The tumor islands also express bcl2 and c-myc proteins. ^[1] The major differential diagnosis of basaloid squamous cell carcinoma is a solid variant of adenoid cystic carcinoma (ACC) and large cell neuroendocrine carcinoma (NEC). ^[6] An ACC differs from the index tumor by focal peripheral presence of basement like material, frequent presence of punched out PAS positive spaces, cylindrical hyaline inclusions and with less frequent presence of pleomorphism, mitosis and necrosis. Also there is no dysplasia or continuity of tumor with the surface epithelium in adnexal tumors such as ACC; whereas in a BSCC there is an adjacent squamous cell carcinoma, dysplasia or carcinoma-in-situ in the overlying epithelium. ^[7] A small cell carcinoma comprises characteristic nuclear molding and crushing artifact, and is rarely connected to surface mucosa. A large cell NEC is characterized by large cells with vesicular nuclei and prominent nucleoli, a mitotic index in excess of 10 per 10 high-power fields, geographic areas of tumor necrosis, and positive staining with appropriate immunohistochemical markers of neuroendocrine differentiation. Clinically, it is an aggressive tumor with high rates of nodal (64%) and distant metastasis (44%). Results of a case-control study by Soriano et al. found a six times higher risk of distant metastasis compared to usual type of SCC. ^[8] Especially B-SCC needs to be differentiated from ACC because of its aggressive course and different treatment regimes. ^[8] The immunohistochemical differentiation of ACC from BSCC is not always easy, as ACCs also express CK, EMA, laminin and CEA. However ACCs characteristically may express S-100, CD117 and alpha1-antitrypsin, which may differentiate from BSCC. ^[9] Ki67 and P53 status examined in BSCCs show absence of significant correlation of their levels with the clinical findings. Ferlito et al. have the biggest published series of BSCC. In their study the 5 year survival is estimated to be 17.5% and metastases (regional and/or distant) were found in 86.7% of their cases. ^[10]

Unresectable primary tumors of the trachea pose a special challenge. Allen et al. reported a case of unresectable adenoid cystic carcinoma of the trachea successfully treated with concurrent chemoradiation (paclitaxel and carboplatin). ^[11] Two other reports of combined chemoradiation as definitive therapy for unresectable carcinoma of the trachea have been published. ^[12],[13] Concurrent chemoradiation is currently considered the treatment of choice for a wide variety of head and neck squamous cell carcinomas. We believe that combining systemic chemotherapy with locoregional radiation is a logical approach to treatment, especially for basaloid squamous cell carcinoma of the trachea, given its tendency to metastasize early after definitive therapy.

As per the best of our knowledge, this is the first case of an unresectable basaloid squamous cell carcinoma of the trachea successfully treated with chemoradiation. The patient remained disease free for two years after treatment. Subsequently in the third year he developed multiple bone and lung metastases and is being treated with palliative chemotherapy.

References

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