Mesenchymal tumours of the uterus: selected topics emphasizing diagnostic pitfalls

Smooth muscle tumours and endometrial stromal tumours represent the two main categories of mesenchymal tumours of the uterus. Although their diagnosis is straightforward in most cases, difficulties arise with particular leiomyoma variants, especially highly cellular leiomyoma (often confused with an endometrial stromal tumour) and leiomyoma with bizarre nuclei, mitotically active leiomyoma, and leiomyomas with hydropic or myxoid change, which may cause concern for leiomyosarcoma. Endometrial stromal tumours including several recently described variants, those with smooth muscle, sex-cord-like or glandular differentiation, or a fibrous-myxoid background are responsible for their own subset of diagnostic problems as are two other entities considered here: high-grade endometrial sarcomas and uterine tumours resembling ovarian sex-cord tumours. This review highlights useful morphologic features as well as immunohistochemical findings that may help in the classification of these often confusing tumours.     

CD10 is a sensitive and diagnostically useful immunohistochemical marker of normal endometrial stroma and of endometrial stromal neoplasms

AIMS: The CD10 antigen is expressed in acute lymphoblastic leukaemia and follicle centre cell lymphoma. A recent study investigating the expression of CD10 in a wide range of non-haematopoietic neoplasms found positive staining in a small number of endometrial stromal sarcomas as well as in normal endometrial stroma. The present study aimed to ascertain whether CD10 positivity is indeed found in normal endometrial stroma and endometrial stromal neoplasms. Staining of a range of tumours which can be confused morphologically with endometrial stromal neoplasms was also undertaken to ascertain whether antibodies against CD10 are of value in a diagnostic sense. METHODS AND RESULTS: Neoplasms included in the study were endometrial stromal nodule (n=1), low-grade endometrial stromal sarcoma (ESS) (n=13), high-grade ESS (n=6), mixed endometrial stromal-smooth muscle tumour (n=1), uterine cellular leiomyoma (n=10), uterine leiomyosarcoma (n=5), adult granulosa cell tumour (AGCT) (n=10), undifferentiated endometrial carcinoma (n=6), uterine carcinosarcoma with an endometrial stromal component (n=1) and type II uterine mesenchymal tumour with sex cord-like elements (n=1). Cases of proliferative (n=5), secretory (n=5) and atrophic (n=3) endometrium were also stained. There was positive staining of stroma but not of glands in all cases of non-tumorous endometrium. There was positive staining of the endometrial stromal nodule and of all low-grade ESS. Staining in these varied but was often diffuse and of moderate to strong intensity. There was positive staining of four of six high-grade ESS, but this was usually focal. There was also positive staining of the endometrial stromal component in the mixed endometrial stromal-smooth muscle tumour and in the uterine carcinosarcoma. Most cellular leiomyomas were completely negative although three exhibited weak positivity. There was some positivity, usually focal or weak, of three of five leiomyosarcomas. Most AGCT and undifferentiated carcinomas were completely negative although one case of each exhibited focal staining. There was focal staining of the type II uterine mesenchymal tumour with sex cord-like elements. CONCLUSION: CD10 is a reliable and sensitive immunohistochemical marker of normal endometrial stroma. Positivity, which is often strong and/or diffuse is found in endometrial stromal nodules and low-grade ESS. Positive staining with CD10, when strong and diffuse, may be useful in distinguishing these tumours from histological mimics, especially cellular leiomyoma and AGCT which are generally negative. In this situation, CD10 should be used as part of a panel which might include desmin and alpha-inhibin depending on the differential diagnosis considered. Positive staining with CD10 in a high-grade uterine sarcoma which is negative with muscle markers might indicate endometrial stromal differentiation and identify a group of neoplasms which it is correct to diagnose as high-grade ESS rather than undifferentiated uterine sarcoma.     

C-kit protein expression in uterine and ovarian mesenchymal tumours

The protooncogene c-kit encoding transmembrane tyrosine kinase receptor protein plays an important role in the signal transduction pathway that regulates cellular growth and repair. Gene product KIT overexpression has been shown in a number of different neoplasms, particularly in mastocytosis and gastrointestinal stromal tumours (GIST). The morphologic similarity of uterine mesenchymal tumours and GIST, and the presence of KIT protein in normal uterine tissue, suggests that uterine sarcomas may have the same c-kit overexpression. The purpose of this study was to determine the overexpression of c-kit protein in uterine and ovarian sarcomas. Immunohistochemical staining using a polyclonal anti-c-kit antibody was performed on tissue blocks from 12 carsinosarcomas, 14 leiomyosarcomas, 8 endometrial stromal sarcomas, 2 adenosarcomas, 1 atypical leiomyoma, 1 leiomyoma with limited experience, and 10 leiomyomas. The slides were evaluated by a semiquantitative method. C-kit was positive in 10 of 12 (83%) carcinosarcomas, 10 of 14 (71%) leiomyosarcomas, 6 of 8 75(%) endometrial stromal sarcomas, 1 of 2 (50%) adenosarcomas, 1 leiomyoma with limited experience, and 1 of 10 (10%) leiomyomas. The uterine sarcomas express c-kit, like GISTs. It seems that KIT may have a significant role in the oncogenesis of mesenchymal tumours of the uterus and ovary.     

Epstein-Barr virus expression within keratinizing nasopharyngeal carcinoma

Three stages of maturation can be seen in keratinizing nasopharyngeal carcinomas. These stages are similar morphologically to basal cells, intermediate and superficial squamous cells seen in normal squamous epithelium. Taking advantage of such a diverse tumour cell population, 10 keratinizing nasopharyngeal carcinoma (NPC) were examined by in situ hybridization for the presence of latent Epstein-Barr Virus (EBV) using EBV encoded RNAs (EBERs) and by immunohistology for the presence of EBV early antigen-diffuse (EA-D) and the 350/220 kd membrane glycoprotein of the EBV. The basal cell-like tumour cells are mainly infected latently with the virus; viral replication was found in isolated intermediate squamous cells, whilst superficial squamous cells are largely depleted of all the viral markers. We used a control series of non-keratinizing nasopharyngeal carcinomas composed of undifferentiated and poorly differentiated tumour cells and EBV latency was present in these tumours. Viral replication was detected by RT-PCR, in the undifferentiated tumours but viral replication was not seen by immunohistology. The possible relationship between EBV life cycle in these tumours and tumour cell differentiation is discussed in the light of these findings. J. Med. Virol. 55:227–233, 1998. © 1998 Wiley-Liss, Inc.     

Epstein-Barr virus and carcinomas: undifferentiated carcinomas but not squamous cell carcinomas of the nasopharynx are regularly associated with the virus.

The Epstein-Barr virus (EBV) is consistently associated with undifferentiated nasopharyngeal carcinoma (NPC). There is, however, conflicting evidence as to whether squamous cell NPCs are also EBV-associated. Moreover, it has been proposed that other epithelial tumours, particularly thymomas and thymic carcinomas, should be included in the group of EBV-associated neoplasias. However, since the viral DNA in these studies was demonstrated only in extracted DNA, the cellular origin of the viral DNA is uncertain. We have therefore investigated 152 epithelial tumours from various sites for the presence of EBV-DNA by in situ hybridization with 35S-labelled probes. Sixty-eight of 77 undifferentiated NPCs showed an EBV-specific autoradiographic signal, thus confirming the strong association of this tumour type with EBV even in geographical areas where undifferentiated NPC is not endemic. None of eight squamous cell NPCs showed an EBV-specific signal. All of 15 carcinomas with a similar morphology to undifferentiated NPC but from different anatomic sites (thymus, tonsil, breast) were EBV-negative as were 9 thymomas, 26 squamous cell carcinomas of the palatine tonsil, and 14 cervical carcinomas. Our results therefore suggest a unique association of EBV with undifferentiated NPC and support concepts assigning different biological properties to undifferentiated NPC as compared with squamous cell NPC.     

Spindle cell squamous carcinoma of the oesophagus: an analysis of 17 cases, with new immunohistochemical evidence for a clonal origin

AIMS: To study the morphological and immunohistochemical characteristics of spindle cell squamous carcinoma of the oesophagus, in order better to understand the histogenesis of this tumour. METHODS AND RESULTS: In this study we analysed the morphological and immunohistochemical characteristics of 17 cases of spindle cell squamous carcinoma of the oesophagus. Most tumours were polypoid, but tumours with an ulcerated and infiltrative pattern were also observed. Histologically, most tumours were of superficial type, with a characteristic morphological aspect consisting of two types of tumour cells, i.e. differentiated squamous cells, and spindle cells with transition zones between the two components. On immunohistochemistry, the squamous cells were positive for cytokeratin and the spindle cells showed variable expression of cytokeratin, vimentin and smooth muscle actin. p53 protein was over-expressed in 10 cases, both tumour cell types showing strong nuclear positivity. In most tumours, E-cadherin was expressed in the squamous cells and absent in the spindle cells. CONCLUSIONS: The similar pattern of p53 protein expression in the two tumour cell types of spindle cell squamous carcinoma of the oesophagus suggests their common origin. The change in adhesion molecule expression with loss of E-cadherin expression may be associated with the acquisition of spindle cell morphology by the squamous tumour cells.     

Tumours in Iceland. 17. Malignant tumours of the oesophagus. Histological classification and epidemiological considerations.

We studied all primary malignancies of the oesophagus diagnosed in Iceland between 1955 and 1984 and reclassified tumours where histological material was available using the WHO classification system. Of a total of 329 tumours diagnosed in the time period, seven were excluded for various reasons. Of the remaining 322 tumours, 178 were in males and 144 in females. The age standardized incidence was 5.3/10(5) for males and 3.1/10(5) for females. The incidence of oesophageal tumours decreased for both sexes during the time period under investigation. Of 250 reclassified tumours (142 in males and 108 in females), squamous cell carcinomas comprised 81.6%. If the undifferentiated tumours are excluded, the squamous group accounted for 89.1% of the remaining tumours. Small cell carcinomas comprised 3.2% of all cases, which was higher than expected. Most of the tumours appear to be located in the middle part of the oesophagus. The vast majority of resected tumours extended through the wall of the oesophagus. A relatively higher proportion of tumours was confined to the submucosal or muscular layers in the latter half of the period. In conclusion, the epidemiological data in our study appear to resemble what is observed in the other Nordic countries for oesophageal tumours, except for slightly higher overall incidence in Iceland, especially for women.     

Recent developments in gastroesophageal mesenchymal tumours

The pathologist’s approach to gastroesophageal mesenchymal tumours has changed dramatically during the last 25 years. In particular, gastrointestinal stromal tumour (GIST) has evolved from a wastebasket mesenchymal tumour category to a precisely defined entity with an increasingly detailed genetic subclassification. This subclassification has brought gastrointestinal mesenchymal neoplasia into the realm of precision medicine, with specific treatments optimised for particular genetic subtypes. Molecular genetic data have also greatly improved our understanding of oesophageal mesenchymal tumours, including the discovery that so‐called ‘giant fibrovascular polyps’ in fact represent a clinically distinctive presentation of well‐differentiated liposarcoma. Here, we will focus on gastroesophageal mesenchymal tumours for which there have been recent developments in classification, molecular genetics or tumour biology: granular cell tumour, ‘giant fibrovascular polyp’/well‐differentiated liposarcoma, plexiform fibromyxoma, gastroblastoma and, of course, GIST.     

Sporadic Cajal cell hyperplasia is common in resection specimens for distal oesophageal carcinoma

Interstitial cell of Cajal (ICC) hyperplasia has been documented in conditions associated with multiple gastrointestinal stromal tumours (GISTs) (familial GIST syndromes, Carney’s triad and von Recklinghausen’s disease) and rarely in the vicinity of sporadic GISTs. The incidence of sporadic ICC hyperplasia and the so-called seedling leiomyoma (SLM) of the lower oesophagus has not been studied in the KIT era. In a retrospective review of 77 consecutive, routinely processed oesophagogastric resection specimens for distal oesophageal carcinoma, we found foci of ICC hyperplasia in 7 of 77 (9.1%) cases and foci of SLM in 17 of 77 (22%) cases. Two types of ICC hyperplasia were recognized: a non-circumscribed type and a nodular expansile type with peripherally compressed myenteric neural tissues. All cases of ICC hyperplasia were vimentin⁺/CD34⁺/CD117⁺. SLMs were desmin⁺/vimentin⁻/CD34⁻/CD117⁻, similar to smooth muscles of the gut wall. In a prospective study of 32 non-carcinomatous specimens from age-matched patients (mostly autopsy cases), we found SLMs in only one case, but we were unable to detect ICC hyperplasia in any of the cases. We concluded that sporadic KIT-positive spindle-cell hyperplasia and SLMs were unexpectedly common in distal oesophageal specimens harbouring carcinomas. The possible mechanisms leading to the development of these putative precursor lesions will be discussed.     

Histochemistry of mucin secreting components in mucoepidermoid and adenosquamous carcinoma of the oesophagus.

AIMS--To determine the direction of differentiation of the mucin secreting components in a rare group of oesophageal tumours--oesophageal squamous cell carcinomas with prominent mucin secreting components (mucoepidermoid carcinomas and adenosquamous carcinomas). METHODS--In a review of 617 cases of primary carcinoma of the oesophagus, 16 cases of squamous cell carcinoma with prominent mucin secreting components were studied using a battery of histochemical techniques. RESULTS--The mucin produced by these tumours was mixed and included a variable content of enzyme labile sialomucin (positive for mucicarmine, periodic acid Schiff, and alcian blue, and sensitive to sialidase digestion and negative for high iron diamine-alcian blue). Retrospective analysis of endoscopic biopsy specimens taken from these tumours showed that mucin was present in five (42%) cases. CONCLUSIONS--The glandular component of this group of tumours histochemically differentiated in the direction of oesophageal glands: examination of the mucin secreting component in squamous cell carcinoma in resected specimens is therefore required for recording the true incidence of this type of tumour.     

Measurement of extent of spread of oesophageal squamous carcinoma by serial sectioning.

OBJECTIVES: (1) To examine the prevalence and extent of intramural metastasis in squamous cell carcinomas of the oesophagus so as to delineate the resection margins for these tumours; (2) to devise an appropriate method for measurement of these lesions which takes into account of the contraction of the specimens after resection. METHODS: Oesophagectomy specimens were prospectively collected from 96 patients (87 males, nine females) with primary oesophageal squamous cell carcinoma over a two year period. The sizes of the tumours were measured in situ, after resection and after application of muscle relaxant (to regain their in situ length). The specimens were then serially sectioned for histological examination. RESULTS: The sizes of the tumours measured after application of muscle relaxant roughly corresponded to those measured in situ. Intramural metastasis was observed in 26% of the cases. Sixty four per cent (16 cases) of these were on the oral side, 72% (18 cases) on the gastric side, and 25% (nine cases) on both sides of the tumours. The most distant extent of intramural metastasis from the primary tumour was from 0.5 cm to 7.7 cm (mean = 3.4 cm) on the oral side, and 0.5 to 9.5 cm (mean 4 cm) on the gastric aspect of the tumour. Intramural metastasis was seen only in patients in whom the primary cancer had deep muscle infiltration. Multiple neoplastic lesions could be detected in 33% of the patients. Both intramural metastasis and multiple neoplastic lesions were associated with extensive lymph node infiltration. However, they had different histological features and extent of infiltration. CONCLUSIONS: Intramural metastasis was frequently observed in oesophageal squamous cell carcinoma. This implies that excision with wide margins should be considered for local control of the disease.     

Lack of CD34 positive stromal cells within angiomyomas (vascular leiomyomas)

AIMS: To investigate the role of CD34 positive stromal cells in the morphogenesis and tumour growth regulation of angiomyomas (vascular leiomyomas). METHODS: Histochemical analysis using monoclonal antibodies to CD34 and CD31 was performed in 10 angiomyomas and their adjacent soft tissue. RESULTS: CD34 positive stromal cells were not seen within the tumour tissue; the thick walled vessels within the tumours lacked CD34 positive stromal cells. In contrast, bundles of CD34 positive stromal cells were detected at the tumour border of all of the angiomyomas and in the adventitial tissue of the surrounding normal vessels. CONCLUSIONS: The lack of CD34 positive stromal cells within an angiomyoma is associated with the characteristic morphology of an angiomyoma.     

Site distribution of oesophagogastric cancer

AIMS: It has been suggested that adenocarcinomas of the lower oesophagus and gastric cardia should be reclassified as oesophagogastric junction (OGJ) cancers. This study aimed to define the frequency of OGJ cancers in a geographically defined population of 4.3 million people. METHODS: All cases of oesophageal and gastric cancer occurring in 1993 were identified by the North Western Regional Cancer Registry. A total of 1192 hospital case notes were reviewed and a study group of 1067 patients was defined. Tumour involvement was documented at individual subsites in the oesophagus and stomach, allowing for tumour presence in more than one oesophageal/gastric subsite. RESULTS: There were 627 tumours in men and 440 in women. The tumour was confined to the oesophagus in 281 (26.3%) cases and to the stomach in 454 (42.6%) cases. The tumour encroached upon or crossed the OGJ in 332 (31.1%) cases. Overall, tumours involved the cardia, OGJ, or lower oesophagus in 633 (59.3%) cases; in 179 (18.5%) cases the tumour involved the lower oesophagus but not the OGJ, and in another 122 (11.4%) cases the cardia was involved but not the OGJ. CONCLUSIONS: Oesophagogastric cancers in this population predominantly involve the OGJ, lower oesophagus, and/or cardia.     

Overexpression of 27-kDa heat shock protein relates to poor histological differentiation in human oesophageal squamous cell carcinoma

AIMS: Various stress conditions such as heat, chemical and mechanical stresses are known to play a major role in oesophageal squamous cell carcinoma development. Our goal was to evaluate whether changes in stress-induced 27-kDa heat shock protein (HSP27) expression could be demonstrated during oesophageal carcinogenesis. METHODS AND RESULTS: HSP27 expression was studied using immunohistochemistry on formalin-fixed, paraffin-embedded tissue sections from 21 oesophageal squamous cell carcinomas occurring in smokers and/or alcohol abusers. Oesophagus from healthy patients (controls) (five), chemical (eight) and infectious oesophagitis (six) were also included in the study. In normal oesophagus, the protein is present only in the upper epithelial layers. In contrast, in chemical or infectious oesophagitis its expression is strong and occurs in all the epithelial layers including the basal layer. In non-tumoral oesophageal mucosa from smoking and/or drinking patients adjacent to invasive carcinoma, the distribution of the protein is patchy and irregular. In malignant areas, HSP27 protein expression increases drastically from dysplastic lesions to invasive carcinoma, being highest in the less differentiated areas. CONCLUSIONS: In human oesophagus, HSP27 expression is induced by various stresses but alcohol and tobacco generate focal perturbations in the stress response. Tumour immunoreactivity for this protein increases with the anaplasia of the tumour, as in some other tumours in which it is considered to play a role in drug resistance. To our knowledge, these data have not been previously described for oesophageal squamous cell carcinoma.     

Basaloid-squamous carcinoma of the upper aerodigestive tract and so-called adenoid cystic carcinoma of the oesophagus: the same tumour type?

Basaloid-squamous carcinoma of the larynx, pharynx and base of tongue and the so-called adenoid cystic carcinoma of the oesophagus are rare but distinctive tumours associated with a grave prognosis. They occur most commonly in elderly males and present at an advanced stage. Our study of four such laryngeal tumours and five such oesophageal tumours shows that they are histologically and immunohistochemically identical, providing support for the idea that they are the same tumour type. They show a biphasic pattern in which basaloid tumour is intimately associated with a neoplastic squamous component which can be invasive or in situ. The basaloid component is in the form of invasive lobules with frequent comedo-necrosis and hyalinization. The constituent cells possess pale pleomorphic nuclei with frequent mitoses. Immunoreactivity for cytokeratin in the basaloid component is remarkable for its absence or weak and focal nature. Review of the literature shows that only a few cases of 'adenoid cystic carcinoma' of the oesophagus are bona fide examples of adenoid cystic carcinoma as it occurs in the salivary glands, while the others are identical to basaloid-squamous carcinoma of the upper aerodigestive tract. Their distinction is important because genuine adenoid cystic carcinoma is much less aggressive than basaloid-squamous carcinoma.     

Nucleolar organizer regions in uterine sarcomas

Summary Nucleolar organizer regions demonstrable by silver staining technique (AgNORs) are loops of nucleolar DNA transcribing to ribosomal RNA. This report quantifies AgNORs in normal endometrium and myometrium, and in leiomyomas and homologous sarcomas of the uterus. The mean AgNOR number in leiomyosarcomas was significantly higher than that in normal myometrium and that in leiomyomas, whereas no significant difference was observed between normal myometrium and leiomyomas. The mean AgNOR count in low-grade endometrial stromal sarcomas was significantly higher than that in normal endometrial stroma, and significantly lower than that in the high-grade variant of the same tumour. The epithelial component of malignant mixed müllerian tumours exhibited a significantly higher mean AgNOR number than normal endometrial epithelium, and the stromal component of these tumours showed a significantly higher mean AgNOR count than normal endometrial stroma and normal myometrium, respectively. The AgNOR count was significantly correlated with the mitotic rate in leiomyosarcomas, in high-grade endometrial stromal sarcomas, and in the epithelial and mesenchymal portions of mixed müllerian tumours, whereas no statistically significant correlation was observed in low-grade endometrial stromal sarcomas. Increased AgNOR counts have been reported for some kinds of malignant tumours in various organs, compared with normal tissues and benign tumours. This study demonstrates a similar increase when homologous uterine sarcomas are compared with histogenetically related normal and neoplastic tissues. AgNOR counting might be a useful adjunct in the classification and grading of uterine tumours.     

Hamartoma--a benign intraluminal tumor of the oesophagus (a case report).

Benign tumours of the oesophagus are rare, representing less than 1% of all oesophageal neoplasms. Most of them are intramural leiomyomas while the other benign tumours are encountered only infrequently; among these pedunculated intraluminal hamartomas form a particularly rare group. We present here one such case.     

Paget's disease of the oesophagus associated with mucous gland carcinoma of the lower oesophagus

AIM: To report a rare case of oesophageal Paget's disease and its rarer combination with submucosal gland carcinoma of the lower oesophagus. METHODS AND RESULTS: A 74-year-old Saudi female was admitted with the complaint of dysphagia. Endoscopic examination showed an ulcerated tumour at the gastro-oesophageal junction. Initial biopsy showed an undifferentiated carcinoma with pagetoid spread in the oesophageal stratified squamous epithelium. Oesophago-gastrectomy specimen showed a lobulated, poorly differentiated mucous gland carcinoma at the gastro-oesophageal junction. The tumour showed focal acinar differentiation and obvious cancerization of the submucosal glands, somewhat similar to the breast lobular carcinoma in situ. One of the isolated and cancerized submucosal glands also showed carcinoma in situ of its duct. Oesophageal surface epithelium showed extensive pagetoid spread, both over and away from the main tumour. The pagetoid tumour cells showed selective positivity for cytokeratin 7, cytokeratin Cam 5.2, BerEP4 and to a lesser extent for CEA. CONCLUSIONS: As far as we know, this is the fifth case report of oesophageal Paget's disease and the first report of its association with the underlying mucous gland carcinoma.     

Benign oesophageal papillomatosis. A case report with a review of the literature.

An 18-year-old boy presented with a four-year history of dysphagia which had been treated repeatedly by endoscopic removal of papillomata of the oesophagus. Eventually, due to increasing dysphagia and repeated recurrences of the papillomata, resection of the affected lower third of the oesophagus was deemed necessary. The resected segment of the oesophagus was carpeted with numerous benign squamous papillomata. The clinical features, radiographic appearances, and pathology of this extremely rare tumour are presented. Only two acceptable cases of oesophageal papillomata can be found in the literature, making this the third case, and apparently the only one with multiple lesions.     

Nucleolar organizer regions in myogenic stromal tumours of the stomach

Summary Silver staining of nucleolar organizer regions (AgNOR) was studied in 26 primary benign and malignant gastric stromal tumours of myogenic origin. The absolute number of AgNOR per nucleus and the size of AgNOR were compared with histomorphologic features of the tumours.The total number of AgNOR per nucleus in epithelioid and spindle cell leiomyosarcomas significantly (p<0.001) exceeded that in leiomyomas, cellular leiomyomas and epithelioid leiomyoblastomas. The mean number or the size of AgNOR did not correlate with the number of mitoses or the tumour size. In addition, large and bizarre AgNOR were seen predominantly in histologically malignant tumours. Only one exceptional epithelioid leiomyoblastoma recurred despite a lack of conventional characteristics of malignancy and a low AgNOR count.Therefore, quantitative determination of the number of AgNOR is a new independent variable in myogenic gastric tumours. It provides additional information for the histopathological evaluation of this heterogenous group of mesenchymal tumours.