Clear cell sarcoma-like tumour of the gastrointestinal tract (CCSLGT) is a rare entity which has been recently described as late as 2003. Only around 70 cases have been reported in the English literature till date. CCSLGT is mostly seen in young adults in the late 20 s and early 30 s. CCSLGT are aggressive tumours. They are similar to the clear cell sarcoma of the soft tissue but lack melanocytic differentiation, retain neuroendocrine differentiation, and have osteoclastic giant cells. EWSR1-CREB1 fusion is characteristic of these tumours. Complete surgical excision is the best treatment option available. They have a high recurrence rate and poor prognosis. Currently, effective chemotherapy or a targeted agent is not available for the management of these tumours. Here, we describe a case of clear cell sarcoma-like tumour of jejunum encountered by us in a young man. The immunohistochemical and genetic profiling of these tumours are also discussed.

Clear cells sarcomas (CCS) are exceptionally rare in the tongue, with, to our knowledge, only three previous reports in anglo-saxon literature. Through our case, we will discuss the differential diagnosis of clear cells tumors of the tongue and bring this tumour closer to the newly described entity of the gastrointestinal tract named \"clear cells sarcoma-like gastrointestinal (SCCLGI)\", recently renamed \"gastrointestinal neuroectodermal tumour (GNET)\". SCCLGI/GNET share morphological and molecular characteristics with SCC but had until then been observed only in the digestive tract. Our case could be a lingual localization of a SCCLGI/GNET. SCC and SCCLGI/GNET characteristic molecular profil involves EWSR1-ATF1 [t(12; 22) (q13; q12)] and EWSR1-CREB1 [t(2; 22) (q34; q12)] fusion genes, but it is not specific of these tumours.

Malignant gastrointestinal neuroectodermal tumour (GNET) is a recently characterised rare and aggressive tumour that typically arises in association with the small intestine of adults. We present a novel case of this entity and expand the spectrum of its reported morphological features. The patient was a 5-year-old female, the youngest reported patient affected by the condition, and presented with extra-abdominal disease. The histopathological features included the presence of a junctional component of the palatal tumour, which mimicked mucosal melanoma, a feature that has not been previously reported in GNET. Whole genome and RNA sequencing was performed that demonstrated the EWSR1-ATF1 translocation characteristic of GNET. Knowledge of this entity and its features, together with careful morphological assessment supplemented by judicious immunohistochemical and molecular studies should enable the correct diagnosis to be established.

Clear cell sarcoma is an uncommon sarcoma which rarely occurs as a primary tumour in the gastrointestinal tract (CCS-GIT). It shares common molecular genetic abnormalities with the more recently described entity, malignant gastrointestinal neuroectodermal tumour (GNET) but is distinguished by its morphological and immunohistochemical findings. The exact nosological relationship between these tumours continues to be debated. In this review, we present two cases of these rare neoplasms from our files and perform a statistical comparison of all published cases to determine if significant differences exist in their clinicopathological features and biological behaviour. Thirteen cases of CCS-GIT and 58 of GNET were included. CCS-GIT occurred more commonly in males (84.6% vs 46.6%, p = 0.01) and in an older age group (median 57 vs 33 years, p < 0.01). There was no significant difference in their location in the gastrointestinal tract, median tumour size and proportion of cases with an EWSR1-ATF1 vs EWSR1-CREB1 fusion. Median survival for CCS-GIT was 13.5 months and for GNET, 9.5 months (p = 0.78). There was no significant difference in the Kaplan-Meier survival curves for either time to first metastasis (p = 0.88) or overall survival (p = 0.18), including after controlling for tumour size using regression models. Our analysis confirms that aside from morphological variations between these tumours, they also exhibit epidemiological and clinical differences. Despite the prevalent perception that GNET is associated with a more aggressive clinical course, our findings indicate that there is no significant difference in their biological behaviour, although both clearly share a bleak prognosis. Further experience is awaited to determine optimal treatment strategies and whether CCS-GIT and GNET would differ in their response to various therapies.