Small Round Blue Cell Tumours of the Sinonasal Area: Our 5 year Experience in a Tertiary Care Centre in India

Abstract

Purpose: The main purpose of this study is to understand the characteristics and management of sinonasal small round blue cell tumors and also to emphasise the role of immunohistochemistry in their diagnosis and on the outcomes after endoscopic/open excision in these patients. Methods: This is a retrospective study conducted at a tertiary care referral centre in India which included 38 patients with sino nasal for a period of 5 years. All the patients were evaluated clinically and radiologically. All cases were confirmed diagnostically with histopathological examination and immunohistochemistry following surgical excision either by endoscopic or open approach. Some of the cases underwent post operative radiotherapy. Results: In our study, among 176 cases diagnosed with Sino nasal malignancies, 38 (21.6%) cases were diagnosed with sinonasal small round blue cell tumors with male to female ratio 1.4:1. Most common histopathological type among all the sinonasal small round blue cell tumors that presented to us was esthesioneuroblastoma i.e., 8 (21%) patients followed by pituitary macroadenoma in 7(8.4%) patients. Other types are undifferentiated squamous cell carcinoma 10(13.1%), craniopharyngioma 8(10.5%), lymphoma 3(7.9%), synovial/spindle cell sarcoma, malignant melanoma and adenocarcinoma 1(2.6%) each. Schwannoma, rhabdomyosarcoma, neuroendocrine carcinoma and neurofibroma 2 (5.2%) each. Conclusion: Sinonasal small round blue cell tumors are extremely rare tumours. Histopathological diagnosis with immunohistochemistry is characteristic of various tumors and is conclusive for diagnosis. Knowledge of these tumor entity is essential as early diagnosis helps in further management in preventing spread to vital structures and improving outcome. Most of the tumors have a multimodality treatment approach which includes surgical excision, radiotherapy and chemotherapy.

Keywords: Endoscopic excision; Esthesioneuroblastoma; Malignant melanoma; Radiotherapy; Rhabdomyosarcoma; SRBCT’s immunohistochemistry; Schwannoma; Sinonasal malignancies; Sinonasal undifferentiated carcinoma; Small round blue cell tumours; Spindle cell tumour; Synovial sarcoma.

Fig. 1

(A,B,C) Esthenioneuroblastoma: Imaging (A) CECT PNS coronal view, (B) MRI Brain and PNS, T1weighted with contrast coronal view showing a enhancing dumbbell shaped tumor (black arrow) in the left nasal cavity with intracranial extension (C) HPE with Hematoxylin and Eosin stain (H&E) showing nests of monotonous cells of SRBCT (D,E,F) Sinonasal Undifferentiated Cell Carcinoma: (D) CT PNS coronal view showing soft tissue opacification involving the right nasal cavity and paranasal area with erosion of the lamina papyracea with extension into the orbit. (E) Intraoperative images showing tumor involving the right maxillary sinus (black arrow) which was excised by external approach using Weber Ferguson incision. (F) HPE with H&E stain showing small round cells presenting in nests and lobules with intracellular bridges (G,H,I) Rhabdomyosarcoma: (G,H) CT PNS, axial view showing soft tissue in left ethmoidal and sphenoid sinus, with similar areas showing FDG uptake indicating metabolically active lesion on PET scan. (I) HPE images H&E stain High magnification showing SRBCT with hypercellular areas with loose myxoid stroma, perivascular condensation of sheets of round cells (red arrow) with rhabdomyoblastic differentiation (J,K,L) Pituitary Macroadenoma: (J,K) MRI Brain and PNS, T1weighted with contrast (J) axial view and (K) coronal view showing enhancement involving the nose and PNS, extending into clivial and petrous regions with intracranial extensions. (L) HPE with H&E stain showing SRBCT which are chromophobic cells with abundant cytoplasm with stippled chromatin and inconspicuous nucleoli

Fig. 2

(A,B) Sinonasal Malignant Melanoma: (A) CT PNS axial view showing soft tissue opacification in the right nasal cavity. (B) Endoscopic view showing blackish coloured mucosal lesion (green arrow) with IHC positive for S-100 and HMB 45, (C,D) Synovial Sarcoma: (C). MRI T1 weighted Brain and PNS showing enhancement with contrast. (D) Excised gross specimen showing a fungating mass and IHC positive for S-100, TLE and BCL2 positive. (E,F) Sinonasal Non Hodgkins Lymphoma: (E) CT PNS coronal view showing soft tissue opacification in the right nasal cavity, maxillary sinus and ethmoid sinus. (F). Excised gross specimen from maxillary sinus with IHC positive for CD3 and CD5

Fig. 3

Sinonasal Intestinal Adenocarcinoma: (A) CT PNS coronal view showing soft tissue opacification involving the left maxillary sinus and nasal cavity. (B) MRI Brain and PNS, T1weighted, axial view showing enhancement with gadolinium contrast with extension into the orbit. (C,D) HPE with H&E stain staining showing (C) low magnification image showing pseudostratified ciliated columnar epithelium with with ulceration and granulation tissue and (D) High magnification showing submucosal stroma with extensive areas of extracellular mucin pools with few floating glands. (E,F,G) IHC showing (E) CDX2 positive, (F) CK7 positive and (J) CK20 positive