Mucinous Carcinoma of the Skin, Primary, and Secondary

Primary Cutaneous Adenoid Cystic Carcinoma in a Rare Location With an Immune Response to a BNT162b2 Vaccine: A Case Report

CASE

In this report, a rare case of primary cutaneous adenoid cystic carcinoma (PCACC) localized in the subcutaneous tissue of the scapular region that grew after BNT162b2 corona virus disease of 2019 (COVID-19) vaccination is presented and may be explained by CD4 and CD8 cell infiltration. The BNT162b2 mRNA vaccine has been associated with a multisystem inflammatory syndrome (MIS-V). A comparable immune reaction could potentially enhance tumor growth rate.

CONCLUSION

Primary cutaneous adenoid cystic carcinomas are rare tumors with unique locations. Further studies with case series are required to establish management algorithms for PCACC and investigate the potential effect of vaccination.

Primary cutaneous mucinous carcinoma of the scalp masquerading as a benign dermatological mass - A case report

INTRODUCTION AND IMPORTANCE

Primary cutaneous mucinous carcinoma (PCMC) is a rare low-grade malignant neoplasm derived from the sweat glands. Local recurrence of PCMC occurs frequently, but these lesions rarely metastasize. Due to the absence of classical demographic and clinical characteristics, PCMCs masquerade as sebaceous cyst, lipoma, pilomatrixoma, chalazion, or squamous cell carcinoma. This misdiagnosis frequently leads to incomplete surgical excision which necessitates further surgical therapy for a curative intent.

CASE PRESENTATION

We present a case of PCMC in a 45-year-old woman which presented as a slow- growing and symptomless nodule in the scalp. After clinical evaluation, the patient had a typical surgical excision for a benign-looking lesion. Histological evaluation of the specimen confirmed a localized PCMC in the scalp with involved surgical margins.

CLINICAL DISCUSSION

A thorough oncological assessment by PET-CT scan and radionuclide scintigraphy was performed. Later, a wide local excision using a gamma probe for intra-operative radionuclide localization of the tumor area and sentinel lymph nodes was done.

CONCLUSION

The patient did not have any regional or distant metastases and remained stable at the time of reporting this case.

Primary Cutaneous Mucinous Carcinoma: A Review of the Literature

BACKGROUND

Primary cutaneous mucinous carcinoma (PCMC) is an exceedingly rare, low-grade tumor that histologically resembles mucinous carcinoma from other primary sites, such as the breast, gastrointestinal tract, and lungs.

OBJECTIVE

The purpose of this article was to review the current literature on PCMC as it relates to epidemiology, clinical presentation, histopathology, immunohistochemistry, treatment, and prognosis.

MATERIALS AND METHODS

An extensive literature review was conducted using PubMed and Ovid MEDLINE to identify articles related to PCMC.

RESULTS

Several hundred cases have been reported in the medical literature, and surgical resection, whenever feasible, is the standard of care.

CONCLUSION

The diagnosis of primary cutaneous mucinous carcinoma is one of exclusion, requiring a metastatic work-up to rule out distant primary. Mohs micrographic surgery is a tissue sparing technique that allows complete margin control of these rare neoplasia.

Histologic and genomic characterization of a primary mucinous carcinoma of the skin

Aims

Primary skin mucinous carcinoma is a rare sweat gland neoplasm with a high local recurrence rate after conventional excision but a low distant-metastasis rate. The genetic underpinning of skin mucinous carcinoma is presently unknown. Here, we sought to define whether the repertoire of somatic mutations of a primary mucinous carcinoma of the skin would be similar to that of mucinous breast carcinomas, given the histologic similarities between these tumor types.

Methods and results

The tumor was situated in the dermis and partially involved the subcutaneous fat. Tumor cells were suspended in periodic acid-Schiff diastaseresistant- positive mucin lakes and expressed cytokeratin 7, synaptophysin and estrogen receptor. DNA samples extracted from microdissected tumor and matched normal tissue were subjected to massively parallel sequencing targeting 410 cancer-related genes. The skin mucinous tumor was found to have a low tumor mutation burden, but to harbor a clonal GATA3 frameshift mutation (p. T418Hfs*89) and amplification of FOXA1, genes not uncommonly altered in breast mucinous carcinomas.

Conclusions

In this primary skin mucinous carcinoma, GATA3 and FOXA1 driver genetic events were identified, consistent with a possible developmental relationship between skin and breast mucinous neoplasms.

Metastatic Endocrine Mucin-Producing Sweat Gland Carcinoma to the Lung: A Case Report

Endocrine mucin-producing sweat gland carcinoma (EMPSGC) is a rare, low-grade neuroendocrine neoplasm previously believed to be indolent in nature. There have only previously been six reported cases of metastases and none of thoracic structures. This case shows a metastatic EMPSGC in a 72-year-old male with a complex oncologic history and is the first reported case of metastases to the lung. As increased recognition of this entity continues to grow, it is important to consider it as part of the differential in mucinous and/or neuroendocrine neoplasms for appropriate management. This case adds to the oncologic literature by demonstrating a rare cutaneous neoplasm and emphasizing its metastatic potential.

Recurrent Neuroendocrine Primary Cutaneous Mucinous Carcinoma of the Scalp After Complete Excision

ABSTRACT

Primary cutaneous mucinous carcinoma is a rare, indolent malignancy with a debated history regarding cell of origin. Recurrence is rare but has been documented in up to a third of cases. Recent literature reviews have recognized 2 possible subtypes-neuroendocrine and nonneuroendocrine- with different possible prognostic implications for patients. We describe a case of recurrent primary cutaneous mucinous carcinoma in a 50-year-old man with subtle neuroendocrine features not initially recognized on routine H&E staining but highlighted by immunohistochemical studies. We underscore the importance of immunohistochemical use in these rare cases and emphasize that awareness of these neuroendocrine and nonneuroendocrine subtypes is essential for a complete diagnosis.

Expression of p40 in Primary Cutaneous Mucinous Carcinoma Versus Primary Mucinous Carcinomas of the Breast and Colon

BACKGROUND

The transcription factor p63 is a homolog of p53, expressed in basal layers of epithelia and myoepithelial cells. Some studies have suggested that p63 may provide utility in differentiating primary versus metastatic mucinous carcinoma of the skin, given its preferential expression in primary adnexal neoplasms. There have been few studies investigating the expression patterns of p40, an isoform of p63, in primary cutaneous mucinous carcinomas.

METHODS

An immunohistochemical panel including p40, CK7, CK20, estrogen receptor, and progesterone receptor was applied to primary mucinous carcinomas of the skin, breast, and colon.

RESULTS

Only a small subset (25%) of primary cutaneous mucinous carcinomas displayed focal positive staining with p40, similar to what has been reported in the literature for p63. All primary mucinous carcinomas of skin and breast labeled positively with CK7, estrogen receptor, and progesterone receptor. Primary colon mucinous carcinomas were only positive for CK20.

CONCLUSIONS

Based on these results, p40 seems to be an insufficient marker for distinguishing primary versus metastatic mucinous carcinoma due to its low rate of positivity in primary cutaneous mucinous carcinomas.

Primary mucinous adenocarcinoma of the eyelid: A case with initial clinical misdiagnosis requiring surgical re-excision of the tumor

Introduction and importance

Primary mucinous adenocarcinoma (PMA) of the skin is a rare condition that is usually seen in elderly patients, most commonly involves the periorbital region as a slow growing mass. Histopathological and immunohistochemical (IHC) stains are of paramount importance for the diagnosis of these lesions, which are usually misdiagnosed either as benign or metastatic mucinous adenocarcinomas.

Case presentation

We herein report a rare presentation of PMA in a 70-year-old male patient who presented with an upper eyelid residual lesion after being incompletely excised elsewhere as an epidermal cyst and was successfully managed by complete surgical excision with frozen section control of the margins and no evidence of recurrence.

Discussion

PMA is a rare sweat gland malignancy that involves the eyelid in 41.9% in the head and neck area and is a disease of the elderly with median age of 60 years and variable reported racial and gender predilection. Diagnosis of PMA is challenging both clinically and histopathologically, which was the case in our patient's initial incomplete excision with the presumed diagnosis of a benign epidermal cyst. Proper final tissue diagnosis and surgical management in our patient ensured his favorable outcome.

Conclusion

Accurate diagnosis of PMA requires a high index of clinical suspicion and accurate histopathological diagnosis aided by proper IHC markers.

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Primary mucinous adenocarcinoma (PMA) is a rare cutaneous sweat gland malignancy.

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A 70-year-old male with eyelid PMA was misdiagnosed clinically elsewhere as an epidermal cyst.

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He underwent surgical re-excision of the tumor with frozen section control of margins.

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The diagnosis of PMA is challenging, and proper surgical complete excision is necessary.

Endocrine mucin-producing sweat gland carcinoma and associated primary cutaneous mucinous carcinoma: Review of the literature

BACKGROUND

Endocrine mucin-producing sweat gland carcinoma (EMPSGC) is a rare, low-grade, cutaneous adnexal carcinoma with neuroendocrine differentiation. It is considered to be a precursor of invasive neuroendocrine type primary cutaneous mucinous carcinoma (PCMC).

OBJECTIVE

To review clinicopathological literature summary of EMPSGC and associated neuroendocrine PCMC from all reported cases and compare its behavior vs non-neuroendocrine PCMC data reported in the literature.

METHODS

A review of English literature of all EMPSGC cases with and without associated PCMC was carried out.

RESULTS

EMPSGC was associated with invasive neuroendocrine type PCMC in 35.7% of cases. We found the recurrence rate of PCMC associated with EMPSGC of about 12.3%, which is much less than the 30% recurrence rate reported for the non-neuroendocrine subtype of PCMC. The non-neuroendocrine subtype of PCMC shows a 4% and 11% rate of distant and lymph node metastasis, respectively, vs EMPSGC-associated neuroendocrine type of PCMC, which is very indolent and only one recent case of locoregional metastasis out of 190 EMPSGC cases has been reported so far.

LIMITATION

Limitation of our study includes data derivation from case reports and case series in the literature.

CONCLUSION

The prognostic benefits for this cohort of patients may be considered in their overall management.

Adenocarcinoma Arising in the Conjunctiva With Periparotid Lymph Node Metastases

PURPOSE

To report a rare case of adenocarcinoma (ADC) arising in the conjunctiva which locally recurred and metastasized to the periparotid lymph nodes.

METHODS

This is a single observational case report.

RESULTS

A 79-year-old male patient was referred to us for a suspected recurrence of conjunctival carcinoma of the right eye. At presentation, we observed an elevated conjunctival lesion with corneal involvement. He was treated with neoadjuvant mitomycin C 0.04% eye drops, followed by surgical excision of the lesion, cryotherapy of the excision margins, and reconstruction with amniotic membrane graft. The tumor was histologically diagnosed as ADC. The negative systemic evaluation and the immunoprofile led us to believe the primitive nature of the tumor. The excision margins were positive, and the patient was lost to follow up for 7 months, and when he came back, a new local recurrence was diagnosed. Then, he received rescue treatment with mitomycin C 0.04% eye drops with complete regression of the lesion. No local recurrence was observed until the 14-month follow-up visit, during which the patient complained of swelling in the right parotid region. Subsequently, he underwent total parotidectomy with neck dissection. Metastasis was found in 3 periparotid lymph nodes. The patient did not receive further treatments, and no recurrences were observed over the following 20 months.

CONCLUSIONS

ADC arising in the conjunctiva is a very rare occurrence. Additional observation is required for the management of this rare conjunctival tumor.

Granuloma Annulare - A Manifestation of Primary Cutaneous Mucinous Carcinoma?

The objective of this report is to present a rare case of primary cutaneous mucinous carcinoma (PCMC) manifesting with granuloma annulare (GA), and to discuss the association as a paraneoplastic phenomenon. A 65-year-old female presented with a painless, slow-growing, cystic nodule less than 1 cm over the left lateral canthus. The clinical presentation was highly suspicious of sebaceous cyst. The histopathologic examination revealed variable sizes of neoplastic cell clusters in a pool of abundant mucin. A focus of palisading lympho-histiocytic infiltrate surrounding a necrobiosis suggestive of granuloma annulare adjacent to the tumor is identified. Series of extensive investigations performed did not reveal any primary origin. GA can rarely be associated with various malignant conditions. Its association and prognostic importance to these conditions are unclear. The presence with certain malignancies and the resolution of GA with the treatment of underlying malignancy are an indicator that this condition can very well be a paraneoplastic phenomenon.

An Update on Endocrine Mucin-producing Sweat Gland Carcinoma: Clinicopathologic Study of 63 Cases and Comparative Analysis

Endocrine mucin-producing sweat gland carcinoma (EMPSGC) is a rare, low-grade adnexal neoplasm with predilection for the periorbital skin of older women. Histologically and immunophenotypically, EMPSGC is analogous to another neoplasm with neuroendocrine differentiation, solid papillary carcinoma of the breast. Both lesions are spatially associated with neuroendocrine mucinous adenocarcinomas of the skin and breast, respectively. EMPSGC is ostensibly a precursor of neuroendocrine-type mucinous sweat gland adenocarcinoma (MSC), a lesion of uncertain prognosis. Non-neuroendocrine MSC has been deemed locally aggressive with metastatic potential, and previous works speculated that EMPSGC-associated (neuroendocrine-type) MSC had similar recurrence and metastatic potential with implications for patient follow-up. Only 96 cases of EMPSGC have been reported (12 cases in the largest case series). Herein, we present 63 cases diagnosed as "EMPSGC" in comparison with aggregated results from known published EMPSGC cases. We aim to clarify the clinicopathologic features and prognostic significance of the neuroendocrine differentiation of EMPSGC and its associated adenocarcinoma and to determine the nosological relevance of EMPSGC association in the spectrum of MSC histopathogenesis. Results established an overall female predominance (66.7%) and average presenting age of 64 years. EMPSGC lesions were associated with adjacent MSC in 33.3% of cases. The recurrence rate for neuroendocrine-type MSC was ~21%, less than the reported 30% for non-neuroendocrine MSC. There were no cases of metastasis. EMPSGC and neuroendocrine-type MSC are distinct entities with more indolent behavior than previously reported, supporting a favorable prognosis for patients.

Extramammary Paget disease of the vulva

Extramammary Paget disease (EMPD) is a rare neoplasm with uncertain histogenesis, usually presenting in the anogenital area, most commonly in the vulva. The disease is characterized by slow grow and high recurrence rates. This article reviews the epidemiological, clinical, morphological, genetic and treatment features of EMPD of the vulva reported in recent years.

Porocarcinoma with areas of mucinous differentiation suggesting multilineage differentiation

Porocarcinoma is an infrequent malignant adnexal carcinoma, with some histopathological variants described, such as the clear cell, the sarcomatoid or the pigmented porocarcinoma. We report an invasive porocarcinoma showing areas of tumor cells floating in prominent dermal mucin, simulating mucinous carcinoma, that we consider a new histopathological variant of porocarcinoma. We report a 74-year-old male with previous history of multiple basal cell carcinomas that presented a nodule on his left temple. Histopathologic study showed a large ulcerated multilobular tumor composed of thickened cords of cells emanating from a hyperplastic epidermis and showing a mixed infiltrative and pushing pattern in the dermis. Poroid differentiation was observed in most of the neoplasm, both in intraepidermal and dermal invasive component. Within the neoplasm a prominent area where these small nests with clear formation of ducts were floating in mucinous pools with few septa intermingled was observed, simulating a primary cutaneous mucinous carcinoma. Cytology, immunohistochemistry and the presence of both neoplastic areas as closely related and with multiple points of connectivity favors the consideration of a composite tumor in this peculiar case. Other differentials are discussed.

Primary mucinous carcinoma of the skin arising from the upper eyelid: A case report and literature review

Primary mucinous carcinoma of the skin (PMCS) is a rare malignant neoplasm of the sweat glands that has an incidence of 1 per 150,000 population. Because of the lack of typical characteristics, it is often misdiagnosed as an epidermoid cyst, pilomatrixoma, or chalazion before resection, with subsequent enucleation performed unintentionally. We present a case of a 51-year-old patient with PMCS in the upper eyelid that was successfully treated at our hospital. Additionally, we reviewed the literature and discussed the diagnosis, primary and adjuvant therapy, and follow-up procedure.

Primary cutaneous mucinous carcinoma of the scrotum: A rare tumor at a rare site - A case report and review of literature

Primary cutaneous mucinous carcinoma (PCMC) is a rare malignant adnexal tumor of eccrine origin with a higher incidence in the head and neck region of the body while scrotal skin involvement is rare. We report a case of a 72-year-old man with ulceration of painless scrotal lesions of 10 years' duration. Histology of the wedge biopsies of the lesions was mucinous carcinoma. Clinical workup excluded noncutaneous primary sites of mucinous carcinoma and distant metastasis. He had wide excision of the scrotal skin lesions with histological findings of nests of malignant cells separated from pool of mucin by fibrocollagenous septae. Periodic acid–Schiff stain was positive; however, immunohistochemical stains for estrogen and progesterone receptors were negative. No local recurrence was observed after 12 months of follow-up. Scrotal PCMC is a rare tumor; this may probably be the first reported case of this tumor in the scrotum. Prognosis was good following surgical excision.

Expression of hormone receptors, adipophilin, and GCDFP-15 in mucinous carcinoma of the skin

BACKGROUND

Primary cutaneous mucinous carcinoma (PCMC) is a rare epithelial tumor with unclear histogenesis.

METHODS

We evaluated the immunohistochemical expression of the estrogen receptor (ER), progesterone receptor (PR), and androgen receptor (AR) in six cases of PCMC. The immunoreactivity of adipophilin and gross cystic disease fluid protein (GCDFP)-15 was investigated to determine the origin of the tumor.

RESULTS

The study included five males and one female aged 50 to 69 years who presented with a cutaneous mass in the face. Immunoreactivity for ER, PR, and AR was observed in all cases, and all cases were negative for adipophilin but positive for GCDFP-15.

CONCLUSIONS

This report is the first to show AR expression in PCMC. All of followed cases manifested indolent clinical course, and the prognostic significance of hormone receptors in PCMC remains unclear. The negative immunoreactivity of PCMC for adipophilin and positivity for GCDFP-15 suggests a more likely relationship to apocrine than to sebaceous glands.

Mucinous Adenocarcinoma of the Scalp: Primary Cutaneous Neoplasm Versus Underlying Metastatic Disease

Primary cutaneous mucinous carcinoma (PCMC) is a rare mucin-producing malignancy derived from epithelial glandular structures. The literature regarding this topic is mostly in the form of case reports and case series. PCMC tends to present in the elderly with predilection for the head and neck and on initial assessment it can be easily mistaken for a simple inclusion cyst. Although PCMC is often indolent in nature, in rare instances it can metastasize and should remain a differential diagnosis in a selected population. The significance in identifying PCMC is reliably differentiating it from metastatic mucinous adenocarcinoma. We present a review of literature and case of PCMC on the scalp of a 67-year-old female.

Endocrine mucin-producing sweat gland carcinoma: Clinicopathologic, immunohistochemical, and molecular analysis of 11 cases with emphasis on MYB immunoexpression

BACKGROUND

Endocrine mucin-producing sweat gland carcinoma (EMPSGC) is a rare low-grade primary cutaneous sweat gland carcinoma with predilection for the periorbital skin in elderly female patients.

METHODS

We describe 11 cases of EMPSGC using a broad panel of immunohistochemical markers including BerEP4, cytokeratin 7, CAM 5.2, synaptophysin, chromogranin, cytokeratin 20, Ki67, progesterone receptor, and estrogen receptor. Calponin (1A4) and p63 were used to detect surrounding myoepithelial cells. We also examined staining with a relatively new marker, MYB. Previous studies of MYB on EMPSGC remain limited. As mucin-rich basal cell carcinoma (BCC) represents a main differential diagnosis and primary cutaneous mucinous carcinoma (PCMC) could appear synchronous with EMPSGC, these lesions were also stained for MYB.

RESULTS

We found strong and homogenous nuclear MYB-expression in 10 EMPSGC cases stained for MYB. MYB staining was not performed in one case. Furthermore, PCMC and mucin-rich BCCs did not express MYB.

CONCLUSION

The strong nuclear MYB-positivity in EMPSGC could be useful as a new surrogate marker, especially in mucin-poor EMPSGC cases. Additionally, the staining of PCMC revealed absent MYB-expression leading to the conclusion that EMPSGC might not represent a precursor lesion for primary cutaneous mucinous carcinoma.

Primary Cutaneous Mucinous Carcinoma with Extramammary Paget's Disease: Eccrine or Apocrine?

Primary cutaneous mucinous carcinoma (PCMC) is an uncommon tumor of the sweat gland origin. The occurrence of PCMC is mostly in middle-aged and older patients, with a slight male predominance. Most cases of PCMC arise on the head, with a preference for eyelids. The histogenesis of PCMC, whether eccrine or apocrine, remains controversial. We report a rare case of PCMC with secondary extramammary Paget’s disease in the groin of a 75-year-old man, which favored an apocrine origin. Furthermore, based on a review of the literature, we provide several histologic clues that can be used to differentiate PCMC from metastatic mucinous carcinoma.

Unusual skin mass (primary cutaneous mucinous carcinoma)

Primary mucinous carcinoma of the skin is a rare malignant tumour of sweat gland origin. Diagnostic concerns include its deceptively benign appearance in some cases and the difficulty in differentiating it from secondary mucinous carcinoma of skin metastasising from a primary source elsewhere. A case of a 75-year-old man is reported who presented with a slowly growing painless mass near the lateral canthus of the right eye for about 2 years. Clinically, a diagnosis of basal cell carcinoma was made whereas histopathology revealed mucinous carcinoma of the skin. The primary source of the tumour could not be found on detailed physical examination and laboratory investigations. Immunohistochemistry, performed later, was consistent with primary cutaneous mucinous carcinoma.

Adnexal Carcinomas Treated With Mohs Micrographic Surgery: A Comprehensive Review

BACKGROUND

Adnexal carcinomas (ACs) are rare cutaneous malignancies of sweat gland or pilosebaceous origin. Optimal treatment and metastatic potential of AC are poorly defined. Mohs micrographic surgery (MMS) has been increasingly used to treat AC.

OBJECTIVE

To review selected primary cutaneous AC and their treatment outcomes with MMS.

MATERIALS AND METHODS

Literature review using PubMed search for articles related to primary cutaneous ACs.

RESULTS

Sebaceous carcinoma treated with MMS recurred and metastasized in 6.4% and 3.7%, respectively. Primary cutaneous mucinous carcinoma treated with MMS recurred and metastasized in 9.6% and 6.4%, respectively. After MMS, 4.7% of microcystic AC recurred with no reported metastases. After MMS, recurrences and metastases of trichilemmal carcinoma or hidradenocarcinoma have not been reported. Two (4.2%) regional lymph node metastases but no distant metastases or local recurrences have been reported in eccrine porocarcinoma. Squamoid eccrine duct tumor, pilomatrix carcinoma, and spiradenocarcinoma treated with MMS are also reviewed.

CONCLUSION

The rarity of ACs and the lack of comparative data on treatment makes conclusive recommendations on treatment difficult. Recent large case series and reviews suggest MMS is a useful and possibly superior treatment for AC and should be considered if primary cutaneous disease is suspected.

Bilateral Primary Mucinous Carcinoma of the Eyelid

The aim of this study is to report a case of bilateral primary mucinous carcinoma of the eyelids. This is a case report and literature review. A 71-year-old female presented with primary mucinous carcinoma of the left upper eyelid, which was excised with Mohs surgery. One year later, she developed primary mucinous carcinoma of the right upper eyelid, which was also treated Mohs surgery. Extensive workup was negative for evidence of an unknown primary carcinoma or metastasis. Primary mucinous carcinoma of the eyelids may occur as multifocal tumors, and bilateral disease is not necessarily indicative of metastatic disease.

Fine needle aspiration cytology of primary cutaneous mucinous carcinoma of axilla-report of a rare case

Primary mucinous eccrine carcinoma is a rare malignant adnexal tumor of older patients. The histopathological features of this tumor are well-established but the cytomorphology of this neoplasm has only been documented in a few cases. The cytology and histology of this tumor may mimic metastatic mucinous carcinoma and may cause a diagnostic dilemma, especially when the tumor is located at axilla. A correct diagnosis is important because the prognosis is better than that of a metastatic mucinous carcinoma. Here we report the cytological and histological features of a case of primary cutaneous mucinous carcinoma of axilla in an elderly male patient.

Reversed cellular polarity in primary cutaneous mucinous carcinoma: A study on tight junction protein expression in sweat gland tumors

Primary cutaneous mucinous carcinoma (PCMC) is a rare sweat gland tumor characterized by the presence of abundant mucin around the tumor islands, but the molecular mechanisms for this structure are not well elucidated. Because mucin is epithelial in nature, it is likely to be produced by epithelial tumor cells, not by surrounding stromal cells. We hypothesized that the abundant mucin is a result of reversed cellular polarity of the tumor. To test this hypothesis, we conducted an immunohistological study to investigate expression of tight junction (TJ) proteins occludin and ZO-1 in PCMC, as well as in normal sweat glands and other sweat gland tumors. Dot-like or linear expression of TJ proteins was observed at ductal structures of sweat glands, and ductal or cystic structures of related tumors. In PCMC, however, TJ protein expression was clearly visible at the edges of tumor cell islands. This study provides evidence to show that the characteristic histological structure of PCMC is caused by inverse polarization of the tumor cells, and that TJ proteins are useful markers of ductal differentiation in sweat gland tumors.

Mucin as a diagnostic clue in dermatopathology

Mucins are high-molecular weight glycoproteins typically found in normal skin in small amounts. There are several reports regarding different types of cutaneous mucinosis. In this report, we discuss mucins in dermatopathology as a diagnostic clue of some well-known entities and some less frequent cutaneous diseases. We also emphasize mucin as a sign in the differential diagnosis between conditions that show histopathological overlap. Lastly, we discuss the locations and circumstances in which mucin could be considered almost normal or physiological.

Proliferative lesion of anogenital mammary-like glands in the setting of Cowden syndrome: case report and review of the literature

Mammary-like glands are normal appendages of anogenital skin and can give rise to epithelial and stromal tumors that closely resemble breast tumors. Cowden syndrome is an autosomal-dominant cancer-predisposition syndrome that is associated with increased risk of various benign and malignant tumors including breast cancers. Here, we report the first case of a proliferative lesion of mammary-like glands in the setting of Cowden syndrome. A 27-year-old female with Cowden syndrome (R130Q-PTEN mutation) presented with a 1-cm tender, polypoid perianal lesion. An excisional biopsy revealed a circumscribed, lobulated lesion with fibromyxoid stroma and epithelial hyperplasia with apocrine and columnar cell changes that was arranged in papillary, micropapillary and focal cribriform architecture. The features strikingly resembled proliferative changes commonly seen in the breast. Interestingly, the patient subsequently developed an atypical complex sclerosing lesion of the breast. Given the increased risk of breast neoplasia in Cowden syndrome, and the morphologic relationship between breast glands and mammary-like glands, this case raises the possibility of an increased risk of neoplasia arising in mammary-like glands in the setting of Cowden syndrome.

Mucinous Adenocarcinoma of the Salivary Gland: A Review of a Rare Tumor

OBJECTIVE

To describe the clinical, demographic, and prognostic features of salivary gland mucinous adenocarcinoma, a rare head and neck malignancy.

STUDY DESIGN

Population-based national cancer registry analysis.

SETTING

Academic medical center.

SUBJECTS AND METHODS

A review was performed with the National Cancer Database from 1998 to 2012. Demographic, clinical, and survival characteristics were compiled and analyzed. Cox multivariate regression was used to identify predictors of survival. Log-rank tests were used to test survival differences unless otherwise specified.

RESULTS

A total of 170 cases were identified. The most common site of involvement was the parotid gland. Rates of nodal and distant metastases were 45.9% and 10.6%, respectively. High histologic grade was associated with nodal disease (P < .001) and advanced-stage disease (P = .006). Overall 5- and 10-year survival rates were 60% and 44%, respectively. Multivariate analysis found tumor size ≥2 cm (hazard ratio, 22.6; 95% confidence interval: 4.06-126.09; P < .001) and distant metastases (hazard ratio, 17.6; 95% confidence interval: 3.75-82.68; P < .001) to predict poor outcomes.

CONCLUSIONS

Mucinous adenocarcinoma of the salivary gland is a rare otolaryngic cancer. Regional metastases and advanced stage are more common with high histologic grade. Tumor size and distant metastases negatively influence survival.

Challenges in the diagnosis of cutaneous adnexal tumours

The diagnosis of cutaneous adnexal neoplasms, a heterogeneous group of entities, is often perceived by practising pathologists as challenging. A systematic approach to diagnosis is necessary for classification of these lesions, which establishes the tumour differentiation (follicular, sebaceous, sweat gland or apocrine) and evaluates histological features differentiating between benign and malignant entities. Consideration of clinical history is a necessary adjunct in evaluation of the adnexal neoplasm, as characteristic anatomical sites are described for many adnexal lesions. In some instances, immunohistochemical studies may also be employed to aid the diagnosis. The differential diagnosis between primary cutaneous adnexal neoplasms and cutaneous metastases from visceral tumours may also be difficult. Clinical, radiological, histological and immunohistochemical characteristics will be further discussed, considering that the correct diagnosis has a significant impact on the patient's management and prognosis.

Primary mucinous eccrine adenocarcinoma - a rare malignant cutaneous adnexal neoplasm at an unconventional site

Primary mucinous eccrine adenocarcinoma, a rare malignant neoplasm of the skin adnexa usually occurs in the head and neck region. The most common sites for its occurrence are the eyelid, the peri-orbital region and the scalp. We report the rare occurrence of primary mucinous eccrine adenocarcinoma of the inguinal region which has been reported in only 1% of cases according to literature search. Since the differentiation from metastatic mucinous carcinomas is difficult, a careful search for primary in the breast, gastrointestinal tract and prostate is mandatory. This case report highlights the importance of precise diagnosis and accurate histological typing of mucinous carcinomas with an emphasis on their role in appropriate patient management along with a brief review of literature.

A tumoriform lesion of the vulva with features of mammary-type fibrocystic disease

: Fibrocystic disease is a common benign lesion of the breast. Variably sized cysts, apocrine metaplasia, fibrosis, calcification, chronic inflammation, and epithelial hyperplasia are the basic morphological changes seen in mammary fibrocystic disease. We report a rare tumoriform lesion of the vulva with features of fibrocystic disease, which seems to be the first description of this condition in the vulva. The pertinent literature is discussed. The reported lesion further demonstrates the analogy between tumors of anogenital mammary-like glands and mammary neoplasms.

Malignant chondroid syringoma of the face with bone invasion

Malignant chondroid syringoma is a very rare type of malignant sweat gland tumor. Diagnosis is based on pathologic features but is complicated by the low frequency of this tumor. The authors report a new case of malignant chondroid syringoma, initially misdiagnosed as basal cell carcinoma, that exhibited very aggressive local behavior and was located on the face, a rare site for this tumor. The authors describe its histopathologic appearance and highlight the importance of including adenoid cystic carcinoma in the differential diagnosis.