Primary Cutaneous Adenoid Cystic Carcinoma: A Clinicopathologic and Immunohistochemical Study of 27 Cases

Perineural Infiltration: A Comprehensive Review of Diagnostic, Prognostic, and Therapeutic Implications

ABSTRACT

Perineural infiltration refers to a neoplastic cell involvement in, around, and through the nerves. It is considered as one of the neoplastic dissemination pathways. Thus, its identification is crucial to establish the prognosis of some malignant skin neoplasms, such as squamous cell carcinoma, and explains the locally aggressive behavior of cutaneous neoplasms, such as microcystic adnexal carcinoma. We have conducted a review of malignant and benign skin tumors in which perineural infiltration has been described, and we also discuss some histopathological findings that may simulate perineural infiltration.

A Rare Case of Primary Cutaneous Basaloid Squamous Cell Carcinoma of the Finger

Abstract is missing (Short communication)

Spiradenoma With Adenoid Cystic Carcinoma-like Changes: A Case Series of This Rare Variant With a Potential Diagnostic Pitfall

Spiradenomas are benign cutaneous adnexal neoplasms with sweat gland differentiation that can manifest a broad spectrum of histomorphologic appearances. While they show a characteristic histopathologic phenotype and clinical management involves surgical excision with a low risk of recurrence, there have been unusual histopathologic variants of spiradenoma reported, including cases with adenoid cystic carcinoma (ACC)-like changes. Primary cutaneous ACC is a low-grade malignancy presenting as a subcutaneous mass with the potential for local invasion, perineural invasion, and high rates of local recurrence after excision. The diagnosis of spiradenomas with ACC-like features can be challenging, especially when only the ACC-like component is present for evaluation. A retrospective analysis of 21 cases of spiradenoma with ACC-like changes were obtained from large academic institutions, was performed, and summarized below. All cases showed background of conventional spiradenoma, and the ACC-like areas represented a component in all lesions. The percentage of ACC-like component ranged from 5% to 40% in all cases. The ACC-like component was multifocal and without pleomorphism, perineural and/or vascular invasion, necrosis, or increased mitotic activity. MYB translocation and protein expression was studied in 16 cases by fluorescence in situ hybridization, polymerase chain reaction, and immunohistochemistry. All studied cases were negative for MYB / NFIB , MYB L1, and MYB F by fluorescence in situ hybridization and polymerase chain reaction and 3 cases were positive for MYB expression by immunohistochemistry. Our study expands on spiradenomas with ACC-like features that ought to be considered in the differential diagnosis of cutaneous neoplasms such as primary cutaneous ACC. Our results indicate that a thorough histopathologic inspection and strict application of well-defined histologic criteria are necessary to support the diagnosis of this unusual histopathologic variant. These tumors can be difficult to diagnose, and awareness of their histomorphologic spectrum will facilitate definitive diagnosis and avoid misdiagnosis with other conditions.

Utility of GLI1 RNA Chromogenic in Situ Hybridization in Distinguishing Basal Cell Carcinoma From Histopathologic Mimics

Basal cell carcinoma (BCC) is the most common human malignancy and is a leading cause of nonmelanoma skin cancer-related morbidity. BCC has several histologic mimics which may have treatment and prognostic implications. Furthermore, BCC may show alternative differentiation toward a variety of cutaneous structures. The vast majority of BCCs harbor mutations in the hedgehog signaling pathway, resulting in increased expression of the GLI family of transcription factors. GLI1 immunohistochemistry has been shown to discriminate between several tumor types but demonstrates high background signal and lack of specificity. In this study, we evaluated the utility of GLI1 RNA chromogenic in situ hybridization (CISH) as a novel method of distinguishing between BCC and other epithelial neoplasms. Expression of GLI1 by RNA CISH was retrospectively evaluated in a total of 220 cases, including 60 BCCs, 37 squamous cell carcinomas (SCCs) including conventional, basaloid, and human papillomavirus infection (HPV)-associated tumors, 16 sebaceous neoplasms, 10 Merkel cell carcinomas, 58 benign follicular tumors, and 39 ductal tumors. The threshold for positivity was determined to be greater than or equal to 3 GLI1 signals in at least 50% of tumor cells. Positive GLI1 expression was identified in 57/60 BCCs, including metastatic BCC, collision lesions with SCC, and BCCs with squamous, ductal, or clear cell differentiation or with other unusual features compared to 1/37 SCCs, 0/11 sebaceous carcinomas, 0/5 sebaceomas, 1/10 Merkel cell carcinomas, 0/39 ductal tumors, and 28/58 follicular tumors. With careful evaluation, GLI1 RNA CISH is highly sensitive (95%) and specific (98%) in distinguishing between BCC and nonfollicular epithelial neoplasms. However, GLI1 CISH is not specific for distinguishing BCC from most benign follicular tumors. Overall, detection of GLI1 RNA by CISH may be a useful tool for precise classification of histologically challenging basaloid tumors, particularly in the setting of small biopsy specimens, metaplastic differentiation, or metastatic disease.

WT1 as a myoepithelial marker: a comparative study of breast, cutaneous, and salivary gland lesions

WT1 immunostain is expressed in various benign and malignant neoplasms, as well as normal myoepithelial cells. WT1 shows differential expression in non-neoplastic, benign, and malignant neoplastic myoepithelial cells of the salivary gland. In this study, WT1 immunostain and other myoepithelial markers were compared to investigate the value of WT1 as a myoepithelial marker, and to delineate the expression profile of WT1 in nonsalivary gland myoepithelial cells. WT1, p63, and calponin immunostains were performed on normal and lesional tissues from the breast (adenosis, sclerosing adenosis, lactating adenoma, nipple adenoma, tubular adenoma, adenomyoepithelioma, and adenoid cystic carcinoma [ACC]), skin (cutaneous mixed tumor, hidradenoma, spiradenoma, and ACC), and salivary gland (pleomorphic adenoma and ACC). The stained slides were digitized and orientated with H&E images and assessed simultaneously using QuPath. A total of 129, 58, and 56 breast, cutaneous, and salivary gland lesions, respectively, were included. There was poor agreement between WT1-p63 and WT1-calponin (κ < 0.1) in all organs, with absence of WT1 expression in normal salivary gland myoepithelium and most ACCs. There were no significant differences in WT1 expression in myoepithelial cells in normal breast tissue and benign breast neoplasms. Compared to pleomorphic adenomas, cutaneous mixed tumors showed lower WT1 expression (P < .001). WT1 is a less sensitive myoepithelial marker than calponin and p63. However, its unique pattern of expression in salivary gland primary for pleomorphic adenomas/cutaneous mixed tumor can favor a diagnosis of benign salivary gland tumors, particularly in small biopsy specimens.

Reappraisal and literature review of primary cutaneous cribriform apocrine carcinoma

Primary cutaneous cribriform apocrine carcinoma (PCCAC) is an exceedingly rare sweat gland carcinoma. Clinically, it most often presents as a singular, asymptomatic nodule or cyst on the extremities of middle-aged patients and follows an indolent course. Both visceral and cutaneous cribriform tumors exist in nature. While a cribriform pattern is well recognized in tumors of visceral organs, there is a paucity in the literature on the defining characteristics for primary cutaneous tumors. Consensus regarding diagnostic criteria, etiology, and management protocols has yet to be achieved. We conducted an extensive literature review using pre-determined search criteria, resulting in 12 identified case reports and series on PCCAC that were subsequently analyzed. All data were compiled to provide a comprehensive update on the existing information regarding clinical presentation, histopathology, and management of reported PCCACs, as well as differential diagnosis, controversial issues, and recommendations for future considerations.

Rare case of primary cutaneous adenoid cystic carcinoma of the abdomen: A case report

Adenoid cystic carcinoma is predominantly a tumor of the parotid glands and can sometimes be found in other glands. In most cases, skin location is usually a metastatic presentation and rarely a primary tumor. We describe the case of a 59-year-old female patient presenting with a 5-mm skin-colored nodule on the abdomen histologically compatible with a primary cutaneous adenoid cystic carcinoma. Extensive workup revealed no other primary source, nor evidence of metastatic disease; therefore, wide local excision was the preferred treatment given the low potential of recurrence. As this adnexal carcinoma is rare and its morphology non-specific clinically, we wanted to raise awareness of this entity and its management.

Adenoid Cystic Carcinoma/Basal Cell Carcinoma of the Prostate: Overview and Update on Rare Prostate Cancer Subtypes

Adenoid cystic carcinoma/basaloid cell carcinoma of the prostate (ACC/BCC) is a very rare variant of prostate cancer with uncertain behavior. Few cases are reported in the literature. Data on treatment options are scarce. The aim of our work was to retrospectively review the published reports. Thirty-three case reports or case series were analyzed (106 patients in total). Pathological features, management, and follow-up information were evaluated. Despite the relatively low level of evidence given the unavoidable lack of prospective trials for such a rare prostate tumor, the following considerations were made: prostate ACC/BCC is an aggressive tumor often presenting with locally advanced disease and incidental diagnosis occurs during transurethral resection of the prostate for urinary obstructive symptoms. Prostate-specific antigen was not a reliable marker for diagnosis nor follow-up. Adequate staging with Computed Tomography (CT) scan and Magnetic Resonance Imaging (MRI) should be performed before treatment and during follow-up, while there is no evidence for the use of Positron Emission Tomography (PET). Radical surgery with negative margins and possibly adjuvant radiotherapy appear to be the treatments of choice. The response to androgen deprivation therapy was poor. Currently, there is no evidence of the use of truly effective systemic therapies.

A Unique Case of Primary Cutaneous Adenoid Cystic Carcinoma Associated with Aplasia Cutis Congenita in a Four-Year-Old Female: A Case Report

Introduction: Primary cutaneous adenoid-cystic carcinoma (PCACC) is a rare malignant tumour reported in only about 450 cases in the literature, with only two adolescent cases reported. PCACC seems to occur between the fifth and seventh decade of life, and the most frequent regions involved are head and neck (46%). Aplasia cutis congenita (ACC) has an incidence of 1:10,000, and it seems to be rarely associated with neoplastic lesions. Interestingly, the association between PCACC and ACC has, so far, never been described. Methods: We report a case of PCACC in the scalp associated with ACC in a four-year-old patient. Discussion: The patient was under follow-up at the dermatology unit, but suddenly a red lesion appeared within the ACC. This red, ulcerated area increased rapidly over six months, so it was surgically removed, and the pathological examination results were suggestive for cribriform PCACC. According to the guidelines for skin tumours, the patient underwent widening resection, and an advancement-sliding skin flap was performed to recreate the scalp. After one year of follow-up, the patient has no local or widespread recurrence of the PCACC, and the surgical scar appears to have healed well. Conclusions: This clinical case is the first known patient with PCACC associated with ACC. A skin excision biopsy should be performed with wide margins to avoid a second widening resection of skin in a similar scenario. Genetic studies may help to identify the origin of this rare association.

Recent Advances on Immunohistochemistry and Molecular Biology for the Diagnosis of Adnexal Sweat Gland Tumors

Simple Summary

Cutaneous sweat gland tumors form an extremely diverse and heterogeneous group of neoplasms that show histological differentiation to the sweat apparatus. Due to their rarity, wide diagnostic range, and significant morphological overlap between entities, their accurate diagnosis remains challenging for pathologists. Until recently, little was known about the molecular pathogenesis of adnexal tumors. Recent findings have revealed a wide range of gene fusions and other oncogenic factors that can be used for diagnostic purposes and, for some, can be detected by immunohistochemistry. Among other organs containing exocrine glands, such as salivary glands, breasts, and bronchi, most of these biomarkers have been reported in homologous neoplasms that share morphological features with their cutaneous counterparts. This review aims to describe these recent molecular and immunohistochemical biomarkers in the field of sweat gland tumors.

Abstract

Cutaneous sweat gland tumors are a subset of adnexal neoplasms that derive or differentiate into the sweat apparatus. Their great diversity, rarity, and complex terminology make their pathological diagnosis challenging. Recent findings have revealed a wide spectrum of oncogenic drivers, several of which are of diagnostic interest for pathologists. Most of these molecular alterations are represented by gene fusions, which are shared with other homologous neoplasms occurring in organs containing exocrine glands, such as salivary and breast glands, which show similarities to the sweat apparatus. This review aims to provide a synthesis of the most recent immunohistochemical and molecular markers used for the diagnosis of sweat gland tumors and to highlight their relationship with similar tumors in other organs. It will cover adenoid cystic carcinoma (NFIB, MYB, and MYBL1 fusion), cutaneous mixed tumor (PLAG1 fusion), cylindroma and spiradenoma and their carcinomas thereof (NF-κB activation through CYLD inactivation or ALKP1 hotspot mutation), hidradenoma and hidradenocarcinoma (MAML2 fusion), myoepithelioma (EWSR1 and FUS fusion), poroma and porocarcinoma (YAP1, MAML2, and NUTM1 fusion), secretory carcinoma (ETV6, NTRK3 fusion), tubular adenoma and syringo-cystadenoma papilliferum (HRAS and BRAF activating mutations). Sweat gland tumors for which there are no known molecular abnormalities will also be briefly discussed, as well as potential future developments.

Primary cutaneous adenoid cystic carcinoma: a clinicopathologic, immunohistochemical, and fluorescence in-situ hybridisation study of 13 cases

AIMS

This study aimed to investigate the clinical, histological, immunohistochemical and chromosomal features of primary cutaneous adenoid cystic carcinoma (PCACC).

METHODS AND RESULTS

We retrospectively analysed 13 cases identified on their clinicopathological features and performed fluorescence in-situ hybridisation (FISH) on six available cases. Head and neck (46.2%) were most commonly involved. The median age was 53 years, with a male predilection. Histologically, tumours were classified as grades 1 (eight), 2 (four) and 3 with high-grade transformation (HGT) (one). The HGT component was demonstrated as poorly differentiated carcinoma with multifocal necrosis and myoepithelial differentiation. Patients with one of the following factors: longest diameter of the lesion (≥ 1 cm), involvement of subcutaneous fat tissue and widely infiltrative border had a relatively higher rate of local recurrence, distant metastasis and death. Five of six cases were confirmed to have MYB translocation, while nuclear staining for MYB proto-oncogene, transcription factor (MYB) protein was found in four cases. During the follow-up (median = 64 months), two patients experienced local recurrences. One patient, who was classified as grade III PCACC with HGT, developed multiple metastases and died of disease. Another patient was alive with multiple metastases.

CONCLUSIONS

This is the largest single-institution study, to our knowledge, of PCACC in an Asian population. We describe the first case of scalp PCACC with HGT, which is the only death case in our series. PCACC tends to recur locally and has metastatic potential. PCACC with HGT has a poor prognosis.

Cutaneous adenoid cystic carcinoma of lower eyelid: Case report of a rare malignant entity

INTRODUCTION

cutaneous adenoid cystic carcinoma is a rare epithelial tumor with slow development, it is most often described in the scalp; palpebral involvement is very rare. And is accompanied by local aggressiveness and frequent recurrence. The aim of this work is to discuss the management and the interest of a close surveillance of adenoid cystic carcinoma.

CASE PRESENTATION

The authors report a case of palpebral cystic adenoid carcinoma in a 65-year-old patient who underwent surgical excision followed by reconstruction of the loss of substance.

DISCUSSION

Cutaneous cystic adenoid carcinoma of the eyelids remains a very rare entity that must be evoked in front of a nodular cutaneous palpebral tumor that progresses slowly. An early diagnosis and a complete excision guarantee a better prognosis.

CONCLUSION

Adenoid cystic carcinoma, because of its local aggressiveness and its capacity to recur despite satisfactory surgical removal, requires long-term surveillance. Its surgery may be responsible for functional and aesthetic sequelae.

Current Diagnosis and Treatment Options for Cutaneous Adnexal Neoplasms with Apocrine and Eccrine Differentiation

Adnexal tumors of the skin are a rare group of benign and malignant neoplasms that exhibit morphological differentiation toward one or more of the adnexal epithelium types present in normal skin. Tumors deriving from apocrine or eccrine glands are highly heterogeneous and represent various histological entities. Macroscopic and dermatoscopic features of these tumors are unspecific; therefore, a specialized pathological examination is required to correctly diagnose patients. Limited treatment guidelines of adnexal tumor cases are available; thus, therapy is still challenging. Patients should be referred to high-volume skin cancer centers to receive an appropriate multidisciplinary treatment, affecting their outcome. The purpose of this review is to summarize currently available data on pathogenesis, diagnosis, and treatment approach for apocrine and eccrine tumors.

Spiradenoma With Adenoid Cystic Carcinoma-Like Features

Spiradenoma is a benign cutaneous adnexal neoplasm that characteristically presents as a painful dermal nodule, often on the head or trunk. It has a distinct histologic phenotype and management involves surgical excision with low risk of recurrence. In comparison, adenoid cystic carcinoma (ACC) is a low-grade malignancy manifesting as an often painless subcutaneous mass with potential for local invasion, perineural extension, and high rates of recurrence after excision. We report the case of a 63-year-old male patient with a recurrent, painful hematoma-like cyst overlying the left lower extremity tibial tuberosity. A firm nodule was located at the base of the cyst, which was histologically consistent with spiradenoma. Interestingly, the lesion contained multifocal ACC-like components composed of epithelial basaloid cells surrounding pseudocystic structures filled with mucinous material. The ACC-like components did not demonstrate infiltration or perineural invasion. To the best of our knowledge, this is the second publication in the English literature regarding spiradenoma with an ACC-like pattern. Although a benign entity, knowledge of this morphological variant of spiradenoma is essential for diagnostic accuracy in these cases. If a limited biopsy captures only the ACC-like component of a spiradenoma, the lesion may be incorrectly diagnosed as ACC.

Homeobox transcription factor engrailed homeobox 1 is a possible diagnostic marker for adenoid cystic carcinoma and polymorphous adenocarcinoma

Diagnostic utility of a homeobox transcription factor, engrailed homeobox 1 (En1) in the histopathology of salivary gland neoplasms was studied. The expression of En1 was immunohistochemically examined in 51 cases of adenoid cystic carcinoma (AdCC) and 143 cases of other salivary gland neoplasms. In all 51 AdCCs, En1 was expressed in 30-100% of tumor cells. In eight of nine polymorphous adenocarcinomas (PACs), En1 was expressed in 40-100% of tumor cells. Less than 5% of tumor cells expressed En1 in three of 12 epithelial-myoepithelial carcinomas, one of 17 basal cell adenomas (BCAs), and one of 34 pleomorphic adenomas (PAs). Among 55 other carcinoma cases, 1-30% of tumor cells expressed En1 in three salivary duct carcinomas (SDCs) ex PA. None of the myoepitheliomas and Warthin tumors expressed En1. When the cut-off value of the percentage of En1-expressing cells was set to 25%, all 51 AdCCs, eight of nine PACs and one SDC ex PA were En1-positive and the others were En1-negative. En1 is expressed consistently in AdCCs, frequently in PACs, but rarely in other salivary gland neoplasms. En1 is a possible diagnostic marker for AdCC and PAC in the histopathology of salivary gland neoplasms.

Tumor with slow-developing and recurring lumps of the external ear with skull base and lung metastasis: A case report

The present case report describes a rare case of recurring lumps on the external ear in a 46-year-old Chinese male with a history of >10 years, who presented with large irregular red lumps on the right temple and with lung and skull base metastasis. The patient had a lesion in the right auricle and experienced recurrence following surgical resection. A thorough systemic evaluation revealed no other obvious abnormalities. The patient was diagnosed with adenoid cystic carcinoma (ACC), a slow-growing form of high-grade adenocarcinoma, and refused any further treatment at the present hospital (The First Affiliated Hospital of Army Medical University). At 2 years post-follow-up, the patient had become more frail but was in good spirits. The present study indicated that ACC is a low-grade and commonly slow-developing malignancy that primarily arises from a salivary gland, with recurring and metastatic characteristics.

Unusual Presentations of Primary and Metastatic Adenoid Cystic Carcinoma Involving the Skin

Adenoid cystic carcinoma (ACC) is most commonly seen in the salivary glands but may occur at other sites. Primary or metastatic involvement of the skin is unusual. We report 2 cases of ACC with unusual presentation. In the first case, a 55-year-old woman presented with a cutaneous lesion on the right shin, and final pathology showed ACC. An extracutaneous origin was excluded by clinical and imaging studies. In the second case, a 49-year-old woman presented with a nodule on the breast, and biopsy confirmed high-grade ACC (>30% solid areas). She underwent lumpectomy and subsequent mastectomy after recurrence. Sixteen months after the initial diagnosis of ACC of the breast, distant metastases at multiple sites, including the skin, were identified. This report will increase awareness of these rare presentations of cutaneous ACC and allow correct diagnosis and appropriate management of such cases.

Analysis of Characteristics and Survival of Primary Cutaneous Adenoid Cystic Carcinoma of the Head and Neck

BACKGROUND/OBJECTIVES

Primary cutaneous adenoid cystic carcinoma (PCACC) is a rare skin tumor. The head and neck (H&N) is the most common anatomical location. Due to limited published cases, its clinical course and management are not well understood.

METHODS

The National Cancer Database (NCDB) was queried for all cases of H&N PCACC diagnosed from 2004 to 2016. Kaplan-Meier (KM) and Cox proportional hazards models were used to determine clinicopathological and treatment factors associated with survival outcomes.

RESULTS

A total of 201 cases were analyzed. The average age of diagnosis was 57.7 years (± SD 15.8). There was a female predilection (57.7%; P < .05) with the most common primary site being the ear (58.2%). The average tumor size was 15.9 mm in diameter. The most common treatment was surgery alone (51.7%) with wide local excision being the common surgery performed (36.3%). 5-year and 10-year OS were 87.0% and 76.0%, respectively. A total of 65.8% of cases were localized (Stage I and II). KM analysis indicated that gender, age, insurance status, Charlson-Deyo Comobordity Score, and stage were significant predictors of OS (P < .05). Cox proportional hazards analysis revealed that patients with both private (HR 0.11, 95%CI [0.019-0.670]; P = .02) and government (HR 0.12, 95%CI [0.019-0.972]; P = .03) health insurance had a significantly decreased hazard of death than patients who were uninsured. Increasing age was associated with an increased hazard of death (HR 1.06, 95%CI [1.016-1.110]; P = .01).

CONCLUSION

This study represents the largest cohort of H&N PCACC studied to date and provides important clinicopathologic information for this rare tumor. Additionally, our results emphasize the importance of health insurance as an independent predictor of survival in PCACC.

Do not break a sweat: avoiding pitfalls in the diagnosis of sweat gland tumors

The group of malignant sweat gland neoplasms is characterized by a wide biologic spectrum, including tumors with indolent behavior, low-grade malignant potential with locally destructive tumor growth and high local recurrence rates and high-grade malignant potential characterized by risk for disseminated disease and disease-related mortality. Reliable diagnosis to predict behavior may be challenging for a number of reasons. The clinical presentation is often nonspecific. Many of the tumors are rare, and they are only infrequently encountered in routine diagnostic practice. A significant subset of tumors shows bland and innocuous histologic features. They are easily mistaken for benign tumors despite their potential for destructive growth and aggressive disease course. At the other end of the spectrum the tumors may resemble poorly differentiated carcinoma or adenocarcinoma and recognition relies entirely on sampling and carful histological examination. The tumors may be inseparable from cutaneous metastases from visceral primaries by morphology and immunohistochemistry, requiring careful clinical correlation and work-up. Conversely, cutaneous metastases are readily mistaken for cutaneous primary tumors. While the presence of a myoepithelial layer is a helpful feature in excluding metastatic deposits, it does not imply benign behavior of sweat gland tumors in general. The above issues and challenges are exemplified in the discussion of selected sweat gland carcinoma in this manuscript, with a focus on recently described entities and those with novel findings.

Immediate Umbilical Reconstruction after a Mohs Micrographic Surgery for Primary Cutaneous Adenoid Cystic Carcinoma Arising in the Umbilicus

Adenoid cystic carcinoma (ACC) is a malignant neoplasm of glands commonly occurs in salivary glands. Primary cutaneous adenoid cystic carcinoma (PCACC) is a rare form of ACC that primarily presents on the skin. Herein, we represent a rare case of PCACC occurred in the umbilicus in a 66-year-old Korean male patient. The patient visited our center with erythematous indurated patch on the umbilicus diagnosed as ACC by incisional biopsy at another center. The diagnosis of PCACC was confirmed by additional histopathologic examination and imaging study. We proceeded Mohs micrographic surgery and reconstructed umbilicus with tacked purse string suture. Local recurrence and distant metastasis were not observed during 30-month follow-up. We report this rare case of PCACC on the umbilicus so that dermatologist can aware of the rare disease. Furthermore, we recommend MMS and tacked purse string suture as effective methods for treatment of PCACC and immediate umbilical reconstruction.

Primary cutaneous adenoid cystic carcinoma on the lower leg

Primary cutaneous adenoid cystic carcinoma (PCACC) is a very rare malignant tumor. Here a case of PCACC on the left lower leg with metastasis to the inguinal lymph node. The tumor resection and the inguinal lymph node dissection were performed under general anesthesia, and the defect was covered with free meshed skin graft. No complication or recurrence has occurred after the surgery.

Small Subset of Adenoid Cystic Carcinoma of the Skin Is Associated With Alterations of the MYBL1 Gene Similar to Their Extracutaneous Counterparts

Adenoid cystic carcinoma (ACC) of the skin is a rare malignant neoplasm histologically identical to homonymous tumors in other organs. Cutaneous ACC has been found to harbor MYB gene activations, either through MYB chromosomal abnormalities or by generation of the MYB-NFIB fusion. In salivary gland ACC, in addition to the MYB gene, alterations in MYBL1, the gene closely related to MYB, have been reported. We studied 10 cases of cutaneous ACC (6 women, 4 men; and age range 51-83 years) for alterations in the MYB, NFIB, and MYBL1 genes, using FISH and PCR. MYB break-apart and NFIB break-apart tests were positive in 4 and 5 cases, respectively. MYB-NFIB fusions were found in 4 cases. The break of MYBL1 was found in 2 cases, and in one of them, the NFIB break-apart probe was positive, strongly indicating a MYBL1-NFIB fusion. In 2 cases, the MYB break-apart test was positive, whereas no MYB-NFIB was detected, strongly suggesting another fusion partner. It is concluded that MYBL1 alterations are detected in primary cutaneous ACC but are apparently less common compared with MYB and NFIB alterations.

Primary cutaneous cribriform apocrine carcinoma: Case report and literature review

Primary cutaneous cribriform apocrine carcinoma is a rare but distinct variant of primary cutaneous apocrine carcinoma and it is considered a low grade malignancy. We herein present a case of primary cutaneous cribriform apocrine carcinoma at the neck of a 26-year-old female. The tumor features a relatively well-circumscribed border and multiple aggregations of mildly pleomorphic epithelial cells with large ovoid nuclei, small nucleoli and abundant eosinophilic cytoplasms. Cribriform and tubular structures are the major architectural patterns. The primary differential diagnosis is cutaneous metastasis from a cribriform visceral carcinoma; others include primary secretory carcinoma of the skin, adenoid cystic basal cell carcinoma and primary cutaneous adenoid cystic carcinoma.

Polymorphous Sweat Gland Carcinoma: An Immunohistochemical and Molecular Study

Polymorphous sweat gland carcinoma is an uncommon low-grade malignant adnexal tumor with a marked predilection for the distal extremities. Histologically, the lesions are characterized by a cellular proliferation showing a combination of growth patterns, including trabecular, solid, tubular, cribriform, or adenoid cystic and pseudopapillary. The immunohistochemical and molecular profile of these tumors has not yet been properly addressed. We have studied 3 cases of polymorphous sweat gland carcinoma using a broad panel of immunohistochemical markers including cytokeratin AE1/AE3, CK5/6, MOC31, p40, p63, p16, chromogranin, synaptophysin, CD56, MIB-1, estrogen receptor, progesterone receptor, androgen receptor, BER-EP4, smooth muscle actin, epithelial membrane antigen, carcinoembryonic antigen, CD117, S100 protein, HBME-1, DOG1, vimentin, and mammaglobin. We also examined for the MYB-NFIB fusion by fluorescent in situ hybridization (ISH) and for human papilloma virus by ISH. Our studies show that cytokeratin AE1/AE3, CK5/6, p40, p63, p16, chromogranin, and CD56 stains were positive in all 3 cases. All 3 cases were negative for MYB-NFIB fusion by fluorescent ISH which rules out adenoid cystic carcinoma. DNA ISH studies for high-risk human papilloma virus were negative in all cases. MIB-1 proliferation index was very high (30%-70% nuclear positivity), supporting a malignant phenotype. The positivity for chromogranin and CD56 suggests partial neuroendocrine differentiation. The differential diagnosis includes metastases from internal malignancies, basal cell carcinoma, and other benign and malignant adnexal neoplasms such as adenoid cystic carcinoma, ductal eccrine carcinoma, and microcystic carcinoma. Positivity for p16 in combination with chromogranin and CD56 may be potentially good markers for differentiating this tumor from other adnexal tumors.

Syringoid Eccrine Carcinoma of the Foot: Report of a Rare Cutaneous Adnexal Neoplasm

Syringoid eccrine carcinoma is a rare malignant adnexal tumor that typically presents in the head and neck region. Involvement of the extremities is uncommon, with only a few cases reported in the literature. Here, we report our experience with a rare case of syringoid eccrine carcinoma occurring on the plantar surface of the right foot in a 47-year-old African American woman. Histologically, incisional biopsy revealed a tumor consisting of tubulocystic structures lined by basaloid cells with an infiltrative growth pattern, extending from the reticular dermis to the deep biopsy margin. Some of the nests and cords of basaloid cells displayed syringoma-like, tadpole morphology. Immunohistochemical analysis showed diffuse immunoreactivity with monoclonal carcinoembryonic antigen, epithelial membrane antigen, cytokeratin 7, S100 protein, and CD117. These morphologic and immunophenotypic features were most consistent with syringoid eccrine carcinoma. Syringoid eccrine carcinoma has a broad differential diagnosis which must be carefully ruled out by morphology, immunohistochemistry, and thorough metastatic survey with imaging studies. Our case highlights the importance of recognizing this rare entity, which is locally destructive and has a propensity for recurrence. To the best of our knowledge, this is the first reported case of syringoid eccrine carcinoma presenting on the sole of the foot.

Lung metastases from cutaneous adenoid cystic carcinoma 23 years after initial treatment

Cutaneous adenoid cystic carcinoma (CACC) is an extremely rare neoplasm of head and neck region, and is characterized by propensity for local recurrence and perineural invasion. Late distant metastases occur usually to lungs. Although patients with lung metastases from CACC cannot be cured, long-term survival may be possible due to its slow-growing malignancy. We report a case of a 69-year-old female with lung metastases from CACC 23 years after initial surgery of scalp nodule.

Topics in histopathology of sweat gland and sebaceous neoplasms

This article reviews several topics regarding sweat gland and sebaceous neoplasms. First, the clinicopathological characteristics of poroid neoplasms are summarized. It was recently reported that one-fourth of poroid neoplasms are composite tumors and one-fourth are apocrine type lesions. Recent progress in the immunohistochemical diagnosis of sweat gland neoplasms is also reviewed. CD117 can help to distinguish sweat gland or sebaceous tumors from other non-Merkel cell epithelial tumors of the skin. For immunohistochemical differential diagnosis between sweat gland carcinoma (SGC) other than primary cutanesous apocrine carcinoma and skin metastasis of breast carcinoma (SMBC), a panel of antibodies may be useful, including p63 (SGC⁺ , SMBC^- ), CK5/6 (SGC⁺ , SMBC^- ), podoplanin (SGC⁺ , SMBC^- ) and mammaglobin (SGC^- , SMBC⁺ ). Comparison of antibodies used for immunohistochemical diagnosis of sebaceous carcinoma (SC) suggests that adipophilin has the highest sensitivity and specificity. Some authors have found that immunostaining for survivin, androgen receptor and ZEB2/SIP1 has prognostic value for ocular SC, but not extraocular SC. In situ SC is rare, especially extraocular SC, but there have been several recent reports that actinic keratosis and Bowen's disease are the source of invasive SC. Finally, based on recent reports, classification of sebaceous neoplasms into three categories is proposed, which are sebaceoma (a benign neoplasm with well-defined architecture and no atypia), borderline sebaceous neoplasm (low-grade SC; an intermediate tumor with well-defined architecture and nuclear atypia) and SC (a malignant tumor with invasive growth and evident nuclear atypia).

Two Different Cell Populations Is an Important Clue for Diagnosis of Primary Cutaneous Adenoid Cystic Carcinoma: Immunohistochemical Study

Primary cutaneous adenoid cystic carcinoma (PCACC) is a very rare malignancy. The differential diagnosis of PCACCs in pathology practice can be difficult and a group of primary and metastatic lesions, including adenoid basal cell carcinoma of the skin, should be considered in the differential diagnosis. Besides histomorphological clues, immunohistochemistry studies are very helpful in the differential diagnosis of PCACC. We report herein a case of PCACC with extensive immunohistochemical studies and review the literature from an immunohistochemistry perspective.

Primary cutaneous adenoid cystic carcinoma with MYB aberrations: report of three cases and comprehensive review of the literature

Adenoid cystic carcinoma (ACC) is a relatively rare slow-growing and often-aggressive epithelial-myoepithelial neoplasm that arises in multiple organs including the skin. The t(6;9) (q22-23;p23-24) translocation, resulting in a MYB-NFIB gene fusion has been found in ACCs from the salivary glands and other organs. Recently, MYB aberrations occurring in a subset (40%) of primary cutaneous ACC (PCACC) examples was described. Herein, we report three additional cases of PCACC harboring MYB aberrations. The tumors presented in three males aged 43, 81 and 55 years old and affected the extremities in the first two patients and the scalp in the third one. None of the patients had history of prior or concurrent ACC elsewhere. Lesions exhibited the classic ACC morphology of nests of basaloid cells arranged in cribriform and adenoid patterns. Sentinel lymph node biopsy was performed in two cases with one case showing lymph node positivity. Fluorescence in situ hybridization with break-apart probes for MYB and NFIB loci revealed that two cases showed MYB rearrangements while one case showed loss of one MYB signal. None of the cases showed NFIB rearrangements. We contribute with three additional cases of PCACC exhibiting MYB aberrations, the apparent driving genetic abnormality in these tumors.

KIT (CD117) Expression in Benign and Malignant Sweat Gland Tumors

KIT (CD117, c-kit) is a receptor tyrosine kinase involved in the tumorigenesis of several neoplasms. KIT is expressed by the secretory cells of normal sweat glands. We studied the KIT expression and KIT mutational status in various benign and malignant tumors of eccrine and apocrine glands. We included a total of 108 cases comprising 10 benign and 6 malignant sweat gland tumors, and KIT expression was immunohistochemically detected (positive rate): 10 syringomas (0%), 8 poromas (25%), 20 mixed tumors (40%), 21 spiradenomas (43%), 1 cylindroma (0%), 5 hidradenomas (40%), 7 syringocystadenoma papilliferum cases (0%), 1 papillary hidradenoma (100%), 2 tubulopapillary hidradenomas (50%), 8 hidrocystomas (29%), 2 adenoid cystic carcinomas (100%), 5 porocarcinomas (20%), 6 apocrine carcinomas (33%), 10 extramammary Paget diseases (30%), 1 spiradenocarcinoma (100%), and 1 syringocystadenocarcinoma papilliferum (0%). Most KIT-positive cells were luminal cells, arising from glandular structures. We performed polymerase chain reaction–single-strand conformation polymorphism for detecting KIT mutational status. All cases showed no mutations at hot spots for KIT (exons 9, 11, 13, and 17). KIT mutation does not seem to be mechanism for KIT expression, but the expression may be from native sweat glands.

Detection of MYB Alterations and Other Immunohistochemical Markers in Primary Cutaneous Adenoid Cystic Carcinoma

Adenoid cystic carcinoma (ACC) can arise in several organs, and prognosis is highly dependent on the primary tumor site. Primary cutaneous ACC has an excellent prognosis compared with salivary or lacrimal ACC. Activation of MYB by gene fusion or other mechanisms has been found in salivary, breast, and lacrimal ACCs but has not been described in cutaneous ACC. We analyzed the histopathologic and immunohistochemical features of 19 primary cutaneous ACCs, 2 periorbital ACCs, and 12 salivary gland ACCs and assessed for MYB activation in primary cutaneous ACC by immunohistochemistry and molecular methods. The presence of perineural invasion differed significantly among ACCs of various sites (83% salivary, 50% eyelid, 11% skin, P=0.0002). Over 90% of all ACCs were grade 1 or 2 and exhibited diffuse (>50%) positivity with CD117, SOX-10, and smooth muscle actin immunostains. CK15 and vimentin showed diffuse positivity in 36% and 57% of cutaneous ACCs, respectively, and were negative or only focally positive in all salivary ACCs (P=0.04 and 0.002). Six of the 11 cutaneous and periorbital ACCs tested with reverse transcriptase polymerase chain reaction and/or fluorescence in situ hybridization had MYB rearrangements including 2 cases that expressed MYB-NFIB fusion transcripts. Diffuse expression of MYB protein assessed by immunostaining was present in 8 of 9 cutaneous ACCs, including cases both with and without MYB rearrangements. These results indicate that cutaneous ACCs possess the same types of MYB alterations as ACCs of other anatomic sites. Vimentin and CK15 appear to have some discriminatory value in differentiating between primary cutaneous and salivary gland ACCs.

Basal cell carcinomas showing histological features generally associated with cutaneous adnexal neoplasms

Basal cell carcinoma (BCC) is the commonest malignant neoplasm in humans. Although a histopathological diagnosis of BCC is straightforward in the vast majority of cases, unusual histological variants can present a diagnostic challenge. A small proportion of BCCs show features which are generally associated with cutaneous adnexal neoplasms. Such changes may involve either the epithelium or the stroma and can mislead the pathologist particularly in small biopsies. Despite the growing evidence which speculate that BCC is a primitive follicular tumor, it is unusual to encounter tumors which actually show definitive signs of adnexal differentiation. This review aims to address this somewhat overlooked aspect of a very common tumor and offers practical guidance to distinguish them from adnexal neoplasms which they might mimic.

CD117 and CD43 are useful adjuncts in the distinction of adenoid cystic carcinoma from adenoid basal cell carcinoma

Distinction of cutaneous adenoid cystic carcinoma (ACC) from adenoid basal cell carcinoma (BCC) is an occasional diagnostic dilemma in dermatopathology.We examined the immunohistochemical staining patterns with CD117 and CD43 in ACCs and BCCs, including BCCs with an adenoid growth pattern, to determine whether a combination of these markers can assist in the differential diagnosis.Fifteen cases each of ACC and BCC, including seven BCCs with a partial or entirely adenoid growth pattern were immunohistochemically stained for CD117 and CD43. The stains were interpreted semi-quantitatively.Staining for CD43 and CD117 was significantly more common in ACC than in BCC. Forty percent of ACCs showed staining for CD43, while no cases of BCC were positive. CD117 was positive in all cases of ACC, with 93% showing moderate or strong staining. BCC were less frequently positive, with only 20% of cases showing labelling of weak or moderate intensity.Immunohistochemical positivity for CD117 and CD43 are likely to be helpful adjuncts in the separation of cutaneous ACC from adenoid BCC.

Morphologically low-grade spiradenocarcinoma: a clinicopathologic study of 19 cases with emphasis on outcome and MYB expression

Spiradenocarcinoma is a rare skin adnexal neoplasm with potential for aggressive behavior, classified histologically into low- and high-grade tumors. Morphologically, low-grade tumors are thought to behave more favorably. Limited information is available, however, with only 18 published cases. To study their clinical behavior, histological features, and the diagnostic value of immunohistochemistry, 19 morphologically low-grade spiradenocarcinomas were retrieved and compared with 21 spiradenomas and cylindromas. H&E-stained sections were reviewed, follow-up was obtained, and immunohistochemistry for Ki-67, p53 and, MYB was performed. The tumors were solitary, measuring 0.8-7 cm (median: 2.7 cm), with a predilection for the head and neck of elderly patients (median age: 72 years; range 53-92) without gender bias. Histologically, the tumors were multinodular and located in deep dermis and subcutis. A pre-existing spiradenoma was present in all cases. The malignant component was characterized by expansile growth with loss of the dual cell population, up to moderate cytological atypia and increased mitotic activity (median: 10/10 HPF; range 1-28). Additional findings included squamoid differentiation (n=9), necrosis (n=7), and ulceration (n=5). P53 expression was variable and no significant differences were noted in the benign compared with the malignant parts of the tumors. In contrast, in the malignant components the Ki-67 proliferative index was slightly increased, and MYB expression was lost. Follow-up (median: 67 months; range: 13-132) available for 16 patients (84%) revealed a local recurrence rate of 19% but no metastases or disease-related mortality. In this large study with long-term follow-up, we demonstrate that spiradenocarcinomas with low-grade morphology pursue an indolent course, characterized by local recurrence only. Metastases and disease-related mortality appear to be exceptional. Lack of MYB expression may be useful as an additional aid in the diagnosis of these challenging tumors.

A subset of prostatic basal cell carcinomas harbor the MYB rearrangement of adenoid cystic carcinoma

Adenoid cystic carcinoma (ACC) is a basaloid tumor consisting of myoepithelial and ductal cells typically arranged in a cribriform pattern. Adenoid cystic carcinoma is generally regarded as a form of salivary gland carcinoma, but it can arise from sites unassociated with salivary tissue. A rare form of prostate carcinoma exhibits ACC-like features; it is no longer regarded as a true ACC but rather as prostatic basal cell carcinoma (PBCC) and within the spectrum of basaloid prostatic proliferations. True ACCs often harbor MYB translocations resulting in the MYB-NFIB fusion protein. MYB analysis could clarify the true nature of prostatic carcinomas that exhibit ACC features and thus help refine the classification of prostatic basaloid proliferations. Twelve PBCCs were identified from the pathology consultation files of Johns Hopkins Hospital. The histopathologic features were reviewed, and break-apart fluorescence in situ hybridization for MYB was performed. All 12 cases exhibited prominent basaloid histology. Four were purely solid, 7 exhibited a cribriform pattern reminiscent of salivary ACC, and 1 had a mixed pattern. The MYB rearrangement was detected in 2 (29%) of 7 ACC-like carcinomas but in none (0%) of the 5 PBCCs with a prominent solid pattern. True ACCs can arise in the prostate as is evidenced by the presence of the characteristic MYB rearrangement. When dealing with malignant basaloid proliferations in the prostate, recommendations to consolidate ACCs with other tumor types may need to be reassessed, particularly in light of the rapidly advancing field of biologic therapy where the identification of tumor-specific genetic alterations presents novel therapeutic targets.