SOX10-Internal Tandem Duplications and PLAG1 or HMGA2 Fusions Segregate Eccrine-Type and Apocrine-Type Cutaneous Mixed Tumors.

Cutaneous mixed tumors exhibit a wide morphologic diversity and are currently classified into apocrine and eccrine types based on their morphologic differentiation. Some cases of apocrine-type cutaneous mixed tumors (ACMT), namely, hyaline cell-rich apocrine cutaneous mixed tumors (HCR-ACMT) show a prominent or exclusive plasmacytoid myoepithelial component. Although recurrent fusions of PLAG1 have been observed in ACMT, the oncogenic driver of eccrine-type cutaneous mixed tumors (ECMT) is still unknown. The aim of the study was to provide a comprehensive morphologic, immunohistochemical, and molecular characterization of these tumors. Forty-one cases were included in this study: 28 cases of ACMT/HCR-ACMT and 13 cases of ECMT. After morphologic and immunohistochemical characterization, all specimens were analyzed by RNA sequencing. By immunohistochemistry, all cases showed expression of SOX10, but only ACMT/HCR-ACMT showed expression of PLAG1 and HMGA2. RNA sequencing confirmed the presence of recurrent fusion of PLAG1 or HMGA2 in all cases of ACMT/HCR-ACMT, with a perfect correlation with PLAG1/HMGA2 immunohistochemical status, and revealed internal tandem duplications of SOX10 (SOX10-ITD) in all cases of ECMT. Although TRPS1::PLAG1 was the most frequent fusion, HMGA2::WIF1 and HMGA2::NFIB were detected in ACMT cases. Clustering analysis based on gene expression profiling of 110 tumors, including numerous histotypes, showed that ECMT formed a distinct group compared with all other tumors. ACMT, HCR-ACMT, and salivary gland pleomorphic adenoma clustered together, whereas myoepithelioma with fusions of EWSR1, FUS, PBX1, PBX3, POU5F1, and KLF17 formed another cluster. Follow-up showed no evidence of disease in 23 cases across all 3 tumor types. In conclusion, our study demonstrated for the first time SOX10-ITD in ECMT and HMGA2 fusions in ACMT and further refined the prevalence of PLAG1 fusions in ACMT. Clustering analyses revealed the transcriptomic distance between these different tumors, especially in the heterogenous group of myoepitheliomas.

The comparison of pure uterine serous carcinoma and mixed tumor with serous component: a single-institution review of 91 cases.

BACKGROUND: Pure uterine serous carcinoma (p-USC) and mixed tumors with serous component (m-USC) are aggressive subtypes of endometrial cancer associated with high mortality rates. This retrospective study aimed to compare clinicopathologic features and outcomes of p-USC and m-USC in a single center. METHODS: This study retrospectively reviewed patients diagnosed with USC at Peking University People's Hospital between 2008 and 2022. T-tests and chi-square tests were used to compare clinicopathological characteristics between p-USC and m-USC. Kaplan-Meier survival curve and Cox regression analysis were used to analyze the impact of clinical and pathological variables on OS and PFS. RESULTS: Among the 91 patients who underwent surgery, 65.9% (n = 60) were p-USC, and 34.1% (n = 31) were m-USC. Patients with p-USC had earlier menopause (P = 0.0217), a lower rate of progesterone receptor(PR) expression (P < 0.001), and were more likely to have positive peritoneal cytology (P = 0.0464). After a median follow-up time of 40 months, 28 (46.7%) p-USC and 9 (29%) m-USC patients had progression disease, 18 (30%) and 8 (25.8%) patients died of their disease. 5-year PFSR were 51.2% and 75.3%, respectively, and 5-year OS rates were 66% and 67.4%. Kaplan-Meier survival analysis showed that p-USC was more likely to relapse than m-USC (P = 0.034), but there was no significant difference in OS. Cox regression analysis showed that lymph node metastasis and surgical approach were risk factors for OS, and myoinvasion depth ≥ 1/2 was an independent risk factor for PFS. CONCLUSIONS: p-USC was more likely to relapse than m-USC, but there was no significant difference in OS between the two subtypes.

[Myoepithelial tumors of soft tissue: A case of mixed tumor]. / Tumeurs myoépithéliales des tissus mous : à propos d'un cas de tumeur mixte.

Myoepithelial neoplasms of soft tissue represent a rare entity which has been described only recently when compared to salivary gland tumors with whom they share histopathological and molecular features. The most common locations are the superficial soft tissues of the limbs and limb girdles. However, they can rarely occur in the mediastinum, abdomen, bone, skin and visceral organs. Benign forms (myoepithelioma and mixed tumor) are more frequent than myoepithelial carcinoma and the latter mostly affects children and young adults. Diagnosis is mainly based on histology, which shows a proliferation of myoepithelial cells of variable morphology with or without glandular structures in a myxoid background, and immunohistochemistry, which shows co-expression of epithelial and myoepithelial markers. Molecular tests are not mandatory, but in selected cases FISH analysis can prove useful as about 50% of myoepitheliomas show EWSR1 (or rarely FUS) rearrangements and mixed tumors show PLAG1 rearrangements. Here, we present a case of a mixed tumor of the soft tissue occuring in the hand with expression of PLAG1 in immunohistochemistry.

Mixed Eccrine Cutaneous Tumor with Folliculo-Sebaceous Differentiation: Case Report and Literature Review.

Background/Introduction: Cutaneous mixed tumor is a rare benign neoplasm that exhibits a wide range of metaplastic changes and differentiation in the epithelial, myoepithelial, and stromal components, which is often confused with various other skin lesions. Case report: We present an unusual case of a 58-year-old woman with a mixed tumor of the upper lip, previously misdiagnosed as adnexal carcinoma on a preoperative biopsy. The excision biopsy shows a well-circumscribed lesion composed of various cells and structures featuring folliculo-sebaceous differentiation embedded in a prominent chondromyxoid stroma. The immunohistochemical study proves the various lineages of differentiation and classifies the neoplasm as the less common eccrine subtype of cutaneous mixed tumor. Discussion: The common embryologic origin of the folliculo-sebaceous apocrine complex leads to a great histological variety of cellular components of mixed tumors and the formation of structures that resemble established types of adnexal neoplasms, which could be a diagnostic pitfall, especially on a small incision biopsy.

An atypical chondroid syringoma with malignant degeneration: Utility of comparative genomic hybridization in confirming the diagnosis.

Chondroid syringoma (CS) represents the cutaneous counterpart of mixed tumor (pleomorphic adenoma) of salivary glands. Definitive diagnosis is made on histopathology and is based on the presence of characteristic epithelial and stromal components. We report a case of an atypical CS arising on the extremity of an elderly male patient. Histomorphologic features of necrosis and cellular atypia raised suspicion for malignant degeneration, an exceptionally rare circumstance in this context. To further support the diagnosis of malignancy, array comparative genomic hybridization was performed from both low and higher grade areas of the tumor. Both regions demonstrated multiple copy number gains and losses, with additional loss of q7p (TP53), loss of 19p, and loss of heterozygosity on16q demonstrated in the more atypical foci. To our knowledge, this is the first case description of malignant degeneration of a CS with correlative microarray analysis. The findings in this case may prove useful in confirming the diagnosis in future ambiguous cases.

Adjuvant Treatment Modalities, Prognostic Factors, and Outcome of the Uterine Carcinosarcoma.

OBJECTIVE: To determine the impact of adjuvant therapy and other factors associated with the recurrence and survival of patients with uterine carcinosarcoma (UCS). METHODS: A total of 102 patients who underwhent surgery for UCS from 1998 to 2017 were included in the analysis. Data were analyzed using Kaplan-Meier methods and Cox proportional hazards regression. RESULTS: At 240 months, the actuarial recurrence rate was 34.3%. Distant recurrence was the most common recurrence pattern. Patients with higher CA 125 levels, sarcoma dominance, cervical involvement, advanced stage, no lymphadenectomy, and residual tumour had a significiantly higher risk of recurrence. Five-year disease-free survival (DFS) and overall survival (OS) were 67% and 77%, respectively. FIGO stage was found to be an independent prognostic factor for DFS and OS. Sarcoma dominance was independently associated with decreased OS. CONCLUSION: Sarcoma dominance is associated with poor survival in UCS. Adjuvant treatment was not found to affect recurrence or survival. Given this finding, more effective postoperative strategies are needed.

Spontaneous multiple cutaneous mixed tumors in Japanese giant salamander Andrias japonicus.

We examined 7 cutaneous mixed tumors in 2 wild-captured Japanese giant salamanders Andrias japonicus. The tumors were either already present and/or increased in size, or newly occurred during capativity. We sampled the 7 tumors from these animals and 3 verrucose protrusions from 3 unaffected animals, as controls, and examined them pathologically and virologically. The tumors (5 mm to 4 cm in size) were papillary protrusions or pendulated on the skin surface. The cut surface of the tumors was white, lobulated, partially hard, and contained mucus. All tumors presented similar histological characteristics of a hyaline structure and exhibited biphasic proliferation, with neoplastic epithelial cells partially composing the pseudo-ductal structure and staining positive for cytokeratin AE1/AE3. Vimentin 3B4-positive blast-like mesenchymal cells proliferated to fill the gaps in the epithelial components. Transition from unique mucous gland to neoplastic tissue was observed. The hyaline structure was stained blue by AZAN stain, Alcian blue-periodic acid-Schiff (PAS) double stain, and toluidine blue (TB) stain of pH 7.0, but was unstained by TB with pH values of 4.1 and 2.5. The mucus in the neoplastic tissue and in the mucous gland in verrucose protrusions was stained blue by Alcian blue-PAS double stain; TB staining at pH 7.0, 4.1, and 2.5 revealed metachromasy. No virus was detected in the tumors. The 7 tumors were diagnosed as cutaneous mixed tumors, and it was confirmed that the neoplastic cells originated from the mucous gland in the dermis. The biological behavior and pathological development of tumors should be elucidated because the tumors have the potential to negatively affect A. japonicus.

Survival and prognostic factors of salivary gland malignant mixed tumor-not otherwise specified: A population-based analysis.

OBJECTIVE: Malignant mixed tumors of the salivary gland are a group of neoplasms comprised of carcinoma-ex-pleomorphic adenoma, carcinosarcoma, and metastasizing pleomorphic adenoma. An alternative classification, malignant mixed tumor-not otherwise (MMT-NOS), is a diagnosis of exclusion for neoplasms that do not fit the previous histologically profiled subtypes. The objective was to provide a comprehensive assessment of MMT-NOS and determine prognostic factors. METHODS: This retrospective cohort study queried the Surveillance, Epidemiology, and End Results database for patient and tumor characteristics of US patients with MMT-NOS of the major salivary glands from 1973 to 2016. Kaplan-Meier and Cox regression analysis were performed to determine 5-year survival and prognostic factors. RESULTS: 434 patients were identified with a mean age at diagnosis of 61.5 years. The majority of neoplasms were high grade and stage (70.8% grade III/IV; 63.8% stage III/IV). Extraparenchymal extension (40.6%) and lymph node involvement (28.5%) were common; distant metastases (2.4%) were rare. Treatment included surgery (93.0%), radiation (51.6%), and chemotherapy (10.4%). Facial nerve sacrifice was common (50.8%). Median survival was 66.5 months. 5-year overall and disease-specific survival were 65.7% and 83.0%, respectively. In multivariate analysis, nodal involvement (HR 7.0; P < 0.001), surgery-radiation-chemotherapy (HR 6.1; P = 0.02), extraparenchymal extension (HR 2.50; P = 0.04), and tumor size >4 cm (HR 1.3; P = 0.03) were prognostic factors. CONCLUSION: Despite high stage and grade at diagnosis, MMT-NOS portends a good 5-year prognosis and low rate of distant metastasis. Prognostic factors were nodal involvement, tumor size, and extraparenchymal extension.

High mitotic index has no prognostic significance in mixed tumor of the vagina.

Mixed tumor of the vagina is a benign neoplasm usually developing in the posterior and distal vaginal wall, close to the hymen, with almost all reported cases exhibiting no or little cellular pleomorphism and rare mitotic activity. The present paper presents a case of a 30 year-old pregnant patient also known to have human immunodeficiency virus (HIV) infection in which a mixed tumor of the vagina was identified and completely surgically removed. Microscopic examination revealed a predominant spindle cell component characterized by high mitotic activity and mild cellular pleomorphism admixed with a minor epithelial component mainly represented by glandular structures lacking atypia and mitoses. Close follow-up showed that the high mitotic index has no prognostic significance in mixed tumor of the vagina, as our patient is well at 3 years after the initial diagnosis.

Liver Transplantation for Cholangiocarcinoma: Insights into the Prognosis and the Evolving Indications.

PURPOSE OF REVIEW: Cholangiocarcinoma (CCA) is a rare malignancy of the biliary ducts that can be classified as intrahepatic, perihilar, or distal based on anatomic location. Although surgical resection can be curative, complete excision with negative margins is often difficult to achieve. In patients with unresectable disease, long-term survival is rarely seen with medical therapy alone. A multimodal treatment approach, including liver transplantation (LT) for select patients with unresectable CCA, should be considered. RECENT FINDINGS: While currently only an approved indication for early, liver-limited, perihilar cholangiocarcinoma, promising results have been achieved for LT in localized intrahepatic disease. The absolute indication for transplant for intrahepatic tumors is currently the subject of multiple investigations. Continued advances in neoadjuvant/adjuvant therapy and better understanding of tumor biology may further augment the number of candidates for surgical therapies, with liver transplant acting as a promising tool to improve patient outcomes. Thorough consideration for any expansion in the indication for liver transplant in malignancy is necessary in order to balance patient outcomes with utilization of the scarce donor organ resources.

Determining the current indications for endoscopic submucosal dissection in patients with Lauren mixed-type early gastric cancer.

BACKGROUND AND AIM: Recent study showed that early gastric cancer (EGC) with Lauren mixed-type (MT) histology is associated with worse prognosis. We aimed to evaluate the clinicopathologic features and prognostic significance of Lauren MT-EGCs that meets the criteria for endoscopic submucosal dissection (ESD). METHODS: We reviewed 2665 patients with EGC who underwent surgery between 2010 and 2015. The clinicopathologic features and invasiveness including lymph node metastasis (LNM) and lymphovascular invasion (LVI) of MT-EGC were compared with those of intestinal type and diffuse type by Lauren histology. RESULTS: Among 2665 patients, EGCs in 241 (9%) patients were classified as MT. Tumor size was larger and depth of invasion was greater than other histology. Among patients with MT-EGC, 16.6% (40/241) showed LNM and 22.8% (55/241) showed lymphatic invasion, which were significantly higher than that of patients with other Lauren types (8.2% and 15.3% in intestinal type and 9.1% and 8.7% in diffuse type, P < 0.001). This finding remained significant even after adjusting for depth of invasion. However, when we analyzed the patient groups who met the absolute or expanded criteria of ESD, no significant difference was observed in the rates of LNM or LVI or cancer mortality by Lauren classification. CONCLUSION: Mixed-type early gastric cancer (MT-EGC) exhibited larger tumor size, greater depth of invasion, and higher risk of LNM and LVI. However, among the patients who met the absolute or expanded criteria of ESD, no significant difference was observed in LNM, LVI, and gastric cancer mortality risk.

Diagnostic accuracy of 3.0T diffusion-weighted MRI for patients with uterine carcinosarcoma: Assessment of tumor extent and lymphatic metastasis.

BACKGROUND: Assessment of tumor extent and lymphatic metastasis of uterine carcinosarcomas is important for treatment planning. PURPOSE/HYPOTHESIS: To evaluate the diagnostic accuracy of 3.0T diffusion-weighted (DW) MRI for patients with uterine carcinosarcoma, in assessment of tumor extent and lymphatic metastasis. STUDY TYPE: Retrospective diagnostic accuracy study. POPULATION: A consecutive cohort of 68 patients with pathologically proved carcinosarcoma between January 2006 and July 2014. FIELD STRENGTH/SEQUENCE: 3T DW MRI. ASSESSMENT: Maximal tumor and uterus size, presence of deep myometrial invasion, cervical invasion, adnexal invasion, lymphadenopathy, and the apparent diffusion coefficient (ADC) values of each tumor were used. Histopathology was the gold standard. STATISTICAL TESTS: Diagnostic accuracy. Logistic regression. RESULTS: In all, 38 patients entered the final analysis, with median age of 58 years (range, 35-79 years). The sensitivity and specificity in detecting deep myometrial invasion, cervical stromal invasion, adnexal invasion, as well as pelvic and para-aortic lymph node metastases were 65% and 72%, 91% and 85%, 50% and 100%, 33% and 89%, and 33% and 100%, respectively. The largest tumor diameters predicted deep myometrium invasion (anteroposterior direction, P = 0.004) and cervical stroma invasion (craniocaudal direction, P = 0.008). Tumor ADCmin significantly predicted the lymphovascular permeation (P = 0.025; odds ratio = 0.96). DATA CONCLUSION: Preoperative DW MRI is useful to assess deep myometrial or cervical stromal invasion in uterine carcinosarcoma, yet the diagnostic performance for detecting adnexal invasion and lymphatic metastasis requires further improvement. LEVEL OF EVIDENCE: 3 Technical Efficacy: Stage 2 J. Magn. Reson. Imaging 2018.

Incidence and histologic features of mixed renal tumors.

BACKGROUND AND OBJECTIVES: Guidelines for management of renal cell carcinoma (RCC) incompletely address the implications of mixed renal tumor histology. We investigate the incidence of mixed renal tumors identified at renal surgery and determine the association with pathologic features. METHODS: Institutional kidney tumor database was reviewed to identify 536 patients who underwent partial or radical nephrectomy. Clinical, demographic, and pathologic data were collected. A linear fixed effects model and logistic regression determined the association of mixed tumor histology with tumor size, stage, grade, and nephrometry score. RESULTS: Three hundred and eighteen men and 218 women with a median BMI of 31 and median tumor size of 3.5 cm were included. 469 (87.5%) patients had pathologic kidney cancer with the most common histologies being clear cell carcinoma in 343 (73.1%) patients, papillary in 81 (17.3%) patients, and chromophobe in 25 (5.3%) patients. Twenty (4.3%) patients had mixed tumors on final pathology. Clear cell RCC was the most common primary pathology in patients with mixed tumor histology (n = 14, 75%) with additional primary tumor histologies included papillary and chromophobe. When considering secondary histologies, 85% were coexistent primary renal cancers while 15% (n = 3) were benign renal tumors. No association of mixed tumor histology and adverse pathologic features was noted. CONCLUSIONS: Mixed tumor histology is an uncommon entity that is not associated with adverse features in a solitary renal mass. These results are especially relevant in discussing the role of renal mass biopsy, and provide further evidence that renal sampling is a valuable tool in the appropriate clinical context.

[Clinicopathologic characterization of malignant mixed tumor of the skin accompanied by eccrine porocarcinoma].

Objective: To investigate the clinicopathologic features, immunophenotype, pathological diagnosis and treatment of malignant mixed tumor (MMT). Methods: Clinical and pathological features including immunohistochemical phenotypes were analyzed in a case of MMT accompanied with eccrine porocarcinoma (EP) involving both hands, diagnosed definitely in January 2018 along with review of relevant literature. Results: A 64-year-old man presented with multiple rash on both hands for 4 years. Three lesions of 0.5 to 2.2 cm were removed for pathological evaluation. The pathological changes on little finger of left and right hands were MMT with EP, whereas that removed from the right ring finger was EP. MMT showed infiltrative growth with vascular wall invasion and consisted of epithelial (glandular or tube differentiation) and mesenchymal components (mucinous and/or cartilage stroma). The endothelial cells showed moderate to severe cytological atypia, nuclear pleomorphism and increased mitotic activity. The glandular component had histological characteristics of syringocarcinoma with moderately atypical chondrocytes but without myoepithelium. EP was composed of basal cells with visible vacuoles in cytoplasm and the presence of tubular and squamous differentiation, along with obvious atypia. Immunohistochemically cavosurface epithelium of glandular differentiation of MMT showed positivity for CK7, EMA and CD117. Myoepithelium showed S-100, CK5/6 and p63 positivity and stromal cells were positive for S-100. Differential diagnoses included metaplastic carcinoma, malignant myoepithelioma and atypical mixed tumor of skin. Conclusions: MMT with EP is extremely rare.The diagnosis of MMT depends on the morphologic features. Immunohistochemical staining is helpful for differential diagnosis. Surgical excision with safety margins is the treatment of choice. Complementary radiotherapy and/or chemotherapy is still controversial. The clinical course of MMT is deemed unpredictable and long-term follow-up is necessary.

Local recurrence of cutaneous mixed tumor (chondroid syringoma) as malignant mixed tumor of the thumb 20 years after initial diagnosis.

Benign cutaneous mixed tumor (chondroid syringoma) is the cutaneous counterpart of the benign mixed tumor (pleomorphic adenoma) of salivary glands, consisting of both epithelial and mesenchymal elements. The incidence of cutaneous mixed tumor is rare, composing <0.01% of all primary skin tumors. Herein, we report a case of malignant mixed tumor which recurred in the right thumb 20 years after the reported initial diagnosis of a benign mixed tumor at this site. Histologically, the lesion consisted of highly atypical and infiltrative cells in cords and ductal structures, with an adjacent focus of residual benign mixed tumor present. Perineural invasion of multiple dermal and subcutaneous nerves was also seen. Immunohistochemical staining was strongly and diffusely positive for CK5/6 and p63, with patchy positive S100 and CK7 staining. Wide excision was performed, with no evidence of recurrence or metastasis 5 years later.

Synchronous malignant mixed Müllerian tumor of the uterus with transitional cell carcinoma of the ovary.

A 55-year-old woman presented with a complaint of post-menopausal bleeding per vaginum. Local examination revealed a mass, protruding from the cervical os, which detached spontaneously. An adnexal mass was felt through the pouch of Douglas on per vaginum examination. Histopathological examination of the avulsed specimen revealed a diagnosis of malignant mixed Müllerian tumor. The patient underwent surgical staging with total abdominal hysterectomy, bilateral salpingo-oophorectomy, left pelvic lymphadenectomy, infracolic omentectomy, and peritoneal wash cytology. Pathological examination revealed a second primary tumor, that is, a transitional cell carcinoma of the ovary. Both the uterine malignant mixed Müllerian tumor and the ovarian transitional cell carcinoma were staged as IA. Subsequently, the patient was treated with adjuvant chemotherapy followed by radiotherapy. The patient is in complete remission at 1 year following the treatment. Synchronous genital tract neoplasms constitute a therapeutic challenge and necessitate an effective multimodality therapeutic approach based on meticulous pathological examination and tumor staging.

Diagnosis and treatment of mixed salivary gland tumor previously diagnosed as cutaneous chondroid syringoma proximal to the oral commissure: A case report.

Subcutaneous tumors of the head and neck resembling cutaneous mixed tumors may be misdiagnosed pleomorphic adenomas of salivary gland origin. Physicians should consider salivary mixed tumors in the differential diagnosis for suspected cutaneous tumors.

Chondroid syringoma of the nose: A rare case report and literature review.

INTRODUCTION AND IMPORTANCE: A chondroid syringoma is an exceptionally rare benign lesion of the sweat glands also known as mixed tumor of the skin (MTS). It can occur in different areas of the head and neck such as the lips, cheek, nose and scalp (Gotoh et al., 2022 [1]). It is usually painless and grows slowly. Based on pathological features it can be differentiated into apocrine or eccrine (Mixed cutaneous tumor: chondroid syringoma a case report, 2019 [2]). CASE PRESENTATION: Our patient presented with a nasal lesion in the left soft triangle, progressively increasing in size. He did not undergo any surgeries to the nose or any history of trauma. Due to the COVID-19 lockdown our patient did not seek early medical advice. In addition, the implementation of facemasks enabled for the concealment of the abnormality, which reduced the need of seeking treatment. CLINICAL DISCUSSION: Chondroid syringoma is a non-ulcerative tumor that grows slowly with an average diameter between 0.5 and 3 cm, however lesions reaching 9 cm have been also seen (Wan et al., 2018 [4]). The mainstay method of management is surgical excision while maintaining the aesthetic appearance of the patient. CONCLUSION: Owing to its rarity, clinical misdiagnosis is common, however absolute diagnosis is achieved by histopathology. This case delineates the rarity of this lesion and the mainstay method of management, which is surgical excision.

Benign mixed mammary tumor with sebaceous differentiation in a dog.

We describe here a case of canine mammary benign mixed tumor with sebaceous metaplasia in the right fifth mammary gland of an eight-year-old, intact female Poodle dog. Grossly, the mass was firm with off-white, poorly lobulated cut surfaces. Histologically, the luminal epithelial cells and myoepithelial cells proliferated with cartilage formation and focal squamous metaplasia. Moreover, a large number of nests of various sizes, which were filled with foamy cells in the center and associated with basaloid reserve-like cells in the periphery, showed sebaceous gland-like structures. Immunohistochemically, myoepithelial cells and reserve-like cells in the metaplastic sebaceous gland-like structures were CK14, α-smooth muscle actin (α-SMA) and p63 positive, suggesting a possibility that these two components may have a common cell of origin.