Pleomorphic adenoma (PA) is the most common benign salivary gland tumor. Histologically, squamous metaplasia has been reported in PA, but has rarely been documented as being extensive enough to cause significant misdiagnosis. Here, we present an unusual case of PA in a 50-year-old female patient presenting with swelling on the postero-lateral aspect of the palate for a week. Histopathologically, the tumor exhibited the features of conventional PA with extensive squamous metaplasia and giant keratotic lamellae in cyst-like areas. Such exuberant squamous metaplasia and keratin can be a diagnostic and prognostic pitfall and lead to overtreatment of the patient.
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We report a case of squamous metaplasia of the pleura observed in a 51 year old man. Squamous metaplasia of serosal surface, and in particular of the pleura, is uncommon. The pathogenesis of squamous metaplasia is obscure, but it may be associated with chronic irritation.
During evaluation of follow-up curettage of endometrial hyperplasia after progesterone treatment, we have noticed that the foci of squamous or morular metaplasia are persistent or even markedly increased after the hyperplastic glands have all disappeared. These observations have led us to study the histological changes of squamous or morular metaplasia in the hyperplastic endometrium after progesterone treatment and to examine the changes of estrogen receptors(ER) and progesterone receptors(PR) to find out, if there is any pathogenetic role of progesterone administration on the squamous or morular metaplasia.
Squamous or morular metaplasia was associated in 21 cases (13.5 %) out of 156 endometrial hyperplasia during the study periods and all of them were associated with complex hyperplasia, but not associated with simple hyperplasia. At follow-up curettage after progesterone treatment, squamous metaplasia newly appeared in 3 cases(20 %), markedly increased in 4 cases(26.7%), persisted in 4 cases(26.7%) and decreased in 4 cases(26.7%), even after hyperplastic glands have all disappeared or were markedly decreased. On immunohistochemical staining, metaplastic foci showed ER- and PR- in 13 cases (87 %) in contrast to the surrounding endometrium and the remaining 2 cases showed minimal ER+ and PR+ confined to several nuclei. Intensity or staining pattern of ER and PR in metaplastic foci were not changed with progesterone treatment. In the background endometrium, intensity of glandular ER+ and PR + was higher than that of the stroma at the initial curettage, however, progesterone treatment predominantly down-regulated glandular ER+ more than stromal ER+. Increment or persistence of squamous metaplasia along the progesterone treatment seemingly would implicate hormonal influences as playing a significant role in the formation of squamous or morular metaplasia and the absence of cellular receptors for these hormones in the metaplastic foci may suggest qualitative changes in the receptors.
An eccrine squamous syringometaplasia (ESS) is defined as a mature squamous metaplasia of the eccrine ducts. The clinical and pathological features of an ESS are presented.
Syringometaplasia is a rare lesion, mostly occuring in the extremities, and as far as we know, no report on the ESS has been published in Korean literature. We experienced a case of an ESS occured in a 15 year-old male, who had a tender erythematous plaque in the right knee. The histologic examination revealed some scattered nests of metaplastic squamous epithelium in the deep dermis, associated with acute nonspecific panniculitis. The importance of the ESS is that it histologically simulates the well differentiated squamous cell carcinoma. The histopathologic findings were discussed and a brief review of the literature was made.
We report a case of Warthin's tumor of the parotid gland in a 53?year?old man, which is incorrectly diagnosed as squamous cell carcinoma. Fine needle aspiration cytology(FNAC) smear obtained from the right parotid gland revealed scattered epithelial cell clusters or nests in a diffuse inflammatory and necrotic background. Some epithelial cells had squamoid appearance showing variable sized bizarre shaped nuclei. They had abundant of dense eosinophilic keratinized cytoplasm. Occasionally, parakeratotic cells were also present. These cytologic findings with significant atypia and necrotic background made diagnosis as squamous cell carcinoma. But, the resection specimen from this patient showed classic Warthin's tumor in addition to abundant areas of inflammation and squamous metaplasia. Metaplastic or infarcted Warthin's tumor in the salivary gland may be confused with false positive diagnosis of malignancy on FNAC. Therefore, cytopathologist should have adequate awareness of potential of erroneous diagnosis in FNAC of Warthin's tumor.
Endometrial mucinous adenocarcinoma occurs in 1-9% of endometrial adenocarcinomas and adenocarcinoma with squamous differentiation in approximately 25%. We report a rare case of mucinous adenocarcinoma with squamous differentiation in a 53-year-old woman. Curetting biopsies of the endometrial lesion were taken twice after hormone replacement therapy, which lasted for four months. Because the squamous differentiation was so extensive, the initial diagnosis based on each curetting specimen was squamous papilloma. A total hysterectomy was performed and the tumor was revealed to be a mucinous adenocarcinoma with squamous differentiation.
We subsequently discussed the pathogenesis and prognosis of this type of tumor.
The occurrence of squamous metaplasia(morule) in colorectal mucosa and adenocarcinoma, althrough rare, has been well documented. In contrast, very little mention has been given to mature squamous cells seen in colorectal polyps or adenomas. A 42-year-old woman presented with a 2-month history of diarrhea and melena. Proctosigmoidoscopy revealed a 4 cm-sized polypoid tumor 20 cm above the anal verge.
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Keratinizing desquamative squamous metaplasia of the transitional epithelium occurs rarely in the upper urinary tract, especially in the ureter. It is associated in most cases with long-standing chronic inflammation but the exact pathogenesis is unknown, and the relationship to cancer has continued to be controversial. More cases should be accumulated for a better assessmnt of this lesion. Recently, we experienced a case of keratinizing desquamative squamous metaplasia in the renal pelvis, adjacent calyces and ureter following acute and chronic pyelonephritis. Herein, we are presenting our case with a review of literatures.