Primary Merkel cell carcinoma of the parotid gland

Small Cell Neuroendocrine Carcinoma of the Parotid Gland: An Uncommon Example of Incompletely Encapsulated Tumor Including S100 Protein-Positive Clear Cells

Small cell carcinoma is rare in salivary glands and has recently been termed small cell neuroendocrine carcinoma. We herein describe an uncommon example arising in the parotid gland. The patient was a 75 yearold Japanese male who had swelling in the right parotid area. He underwent a superficial lobectomy and, after a histological diagnosis was made, a total parotidectomy. Histologically, the tumor had a thick hyalinized capsule that was incomplete, beyond which the tumor invaded into the surrounding parotid parenchyma. The tumor consisted of typical small basophilic cells intermingled with bland clear cells, between which a gradual transition was observed both inside and outside the capsule. Small basophilic cells were immunoreactive for chromograninA as well as synaptophysin, while clear cells were positive for S100 protein. The Ki-67 labeling rate reached 30-40% at the high points of small basophilic cells, but clear cells were minimally labelled. The present case was considered a dedifferentiated carcinoma of the parotid gland, possibly with acinic cell carcinoma as a precursor. This tumor could also be considered a "mixed exocrine-endocrine carcinoma," which may explain the histogenesis of neuroendocrine carcinomas in non-endocrine organs that are not included in the diffuse (dispersed) neuroendocrine system, such as the parotid gland.

Merkel cell carcinoma of unknown primary: Clinical presentation and outcomes

BACKGROUND

Merkel cell carcinoma (MCC) is a rare, aggressive cutaneous malignancy that usually occurs in the head/neck or extremities. However, there are reports of MCC developing in the lymph nodes or parotid gland without evidence of a primary cutaneous lesion.

METHODS

We reviewed 415 patients with biopsy-proven MCC. Patients with MCC of unknown primary (n = 37, 9%, MCCUP) made up the study cohort. The primary endpoints of the study were rate of recurrence, disease-free survival, and overall survival.

RESULTS

Patients with MCCUP presented with tumors in lymph nodes (n = 34) or parotid gland (n = 3). Nodal disease was most commonly detected in the inguinal/external iliac (n = 15) or axillary (n = 14) regions. The mean age at diagnosis was 70 years and 24% were female. Patients presented with distant metastases in 24.3% of cases. Patients with stage IIIA disease treated with regional lymph node dissection (RLND) had a lower risk of disease recurrence (hazard ratio 0.26, p = 0.046). Recurrence-free survival was 59.3% at 5 years. Disease-specific survival was 63.3% at 5 years.

CONCLUSION

Patients with MCCUP have a high risk of recurrence and mortality. The optimal treatment for MCCUP has yet to be elucidated, although therapeutic RLND appears beneficial for these patients.

Primary Parotid Merkel Type Small Cell Neuroendocrine Carcinoma with Oligometastasis to the Brain and Adrenal Gland: Case Report and Review of Literature

Oligometastatic disease is a hypothesized intermediate stage of disease between localized and widespread metastatic cancer. Localized treatment of oligometastatic lesions may offer survival advantages in addition to systemic treatment. In this case report, we describe a patient who presented with small cell neuroendocrine carcinoma "Merkel type" (SNECM) of the parotid gland which had metastasized to the brain and adrenal gland. He was treated with chemotherapy followed by stereotactic radiotherapy and volumetric modulated arc therapy for oligometastasis. He maintains good functional status with low burden of disease at 20-months after diagnosis. SNECM is a rare and aggressive parotid cancer with immunohistochemical and morphologic similarities to Merkel cell carcinoma (MCC). There are only 44 cases of parotid SNECM in the English literature. This is the first case to describe management of oligometastatic SNECM and we review literature on management of both SNECM and metastatic MCC.

Merkel Cell Carcinoma of the Hand: A Case Report and Review of the Literature

Background: Merkel cell carcinoma (MCC) is a relatively rare and aggressive cutaneous neuroendocrine malignancy characterized by high incidence of local recurrence, distant metastases, regional nodal metastases, and high mortality. Clinically, MCC presents as a persistent asymptomatic red/pink shaped nodule, usually smaller than 2 cm with nontender intracutaneous swelling, with rapidly growing localized disease with lymph node metastases preceding distant metastases. Because of its rare nature and the lack of comprehensive understanding of the disease, management of MCC has been controversial. Methods: An 87-year-old retired Caucasian male with a history of tobacco use, chronic sun exposure, and multiple squamous and basal cell carcinomas presented with a 1.8 × 1.3 cm red, nontender nodule on the dorsum of the proximal phalanx of the left long finger first noticed 6 months prior to presentation. Biopsy was consistent with MCC after which he was treated with wide local excision, full-thickness skin grafting, and sentinel lymphadenectomy (1/4 nodes positive) followed by adjuvant radiation therapy. Results: He recovered appropriately and was clinically and radiographically disease free at 2.5-year follow-up. Conclusion: Although it remains rare, MCC has increased in incidence over the last several decades and has a predilection to occur over sun exposed areas. Highly aggressive, it has a high incidence of regional and distant metastasis as well as local recurrence. As a result, it is important that practitioners involved in the care of skin and hand lesions be aware of this condition and the need for a multidisciplinary treatment approach.

Primary retroperitoneal Merkel cell carcinoma: Case report and literature review

BACKGROUND

Merkel cell carcinoma (MCC) is an aggressive cutaneous neuroendocrine carcinoma that affects elderly patients and typically arises in sun-exposed skin. The disease is very rare and only few cases present with no apparent skin lesion. In the retroperitoneum there are only two cases reported in the literature.

CASE PRESENTATION

We report a case of a 54-year-old Mexican male with MCC, which presented as a large retroperitoneal mass. Pathological and immunohistochemical analysis of the transabdominal CT-guided biopsy specimen revealed a MCC. The patient underwent preoperative chemotherapy followed by a laparotomy and the mass was successfully excised.

DISCUSSION

There are two possible explanations for what occurred in our patient. The most plausible theory is the retroperitoneal mass could be a massively enlarged lymph node where precursor cells became neoplastic. This would be consistent with a presumptive diagnosis of primary nodal disease. Moreover, metastasis to the retroperitoneal lymph nodes has been reported as relatively common when compared to other sites such as liver, bone, brain and skin. The less probable theory is the non-described "regression" phenomena of a cutaneous MCC, but we are not found a primary skin lesion.

CONCLUSION

Preoperative chemotherapy and excision of the primary tumor is the surgical treatment of choice for retroperitoneal MCC. We propose that further studies are needed to elucidate the true efficacy of chemotherapy in conventional and unconventional patients with MCC.

Chemotherapy compliance in high-risk Merkel cell carcinoma treated with chemoradiotherapy

OBJECTIVE

To evaluate chemotherapy (CT) compliance in patients treated with chemoradiotherapy (CRT) for high-risk Merkel cell cancer (MCC).

METHODS

Data from three prospective clinical trials in high-risk MCC performed by the Trans-Tasman Radiation Oncology Group were included in this analysis. Patients were treated with one of two carboplatin-based CT schedules and standardised radiotherapy (RT) to the primary site and nodes to a dose of 50-60 Gy in 25-30 fractions. Patients' baseline characteristics were analysed using χ² tests to determine compliance factors for completing CT. A Cox univariate analysis was performed to assess the impact of CT compliance on time to locoregional failure, time-to-distant failure, time-to-recurrence and time-to-death.

RESULTS

A total of 88 patients were identified, with a median follow up of 38.5 months. Of these, 75 (85%) completed CT (median age 64.2 years, range 62.0-66.4), while 13 did not (median age 72 years, range 68.1-75.9), P = 0.006. Women comprised 18/75 patients who completed CT and 7/13 patients who did not complete it (P = 0.03). Performance status, site, stage, surgical margins, RT dose and toxicity did not impact on their CT compliance. At 5 years, 26% of patients had locoregional relapse, 26% had distant failure and 34% had died.

CONCLUSIONS

In this small cohort of patients treated with CRT for high-risk MCC, older age and female sex were associated with failure to complete CT. Severe acute skin and haematological toxicity did not correlate with failure to complete CT.

The impact of preradiation residual disease volume on time to locoregional failure in cutaneous Merkel cell carcinoma--a TROG substudy

PURPOSE

This study evaluated the impact of margin status and gross residual disease in patients treated with chemoradiation therapy for high-risk stage I and II Merkel cell cancer (MCC).

METHODS AND MATERIALS

Data were pooled from 3 prospective trials in which patients were treated with 50 Gy in 25 fractions to the primary lesion and draining lymph nodes and 2 schedules of carboplatin based chemotherapy. Time to locoregional failure was analyzed according to the burden of disease at the time of radiation therapy, comparing patients with negative margins, involved margins, or macroscopic disease.

RESULTS

Analysis was performed on 88 patients, of whom 9 had microscopically positive resection margins and 26 had macroscopic residual disease. The majority of gross disease was confined to nodal regions. The 5-year time to locoregional failure, time to distant failure, time to progression, and disease-specific survival rates for the whole group were 73%, 69%, 62%, and 66% respectively. The hazard ratio for macroscopic disease at the primary site or the nodes was 1.25 (95% confidence interval 0.57-2.77), P=.58.

CONCLUSIONS

No statistically significant differences in time to locoregional failure were identified between patients with negative margins and those with microscopic or gross residual disease. These results must, however, be interpreted with caution because of the limited sample size.

Merkel cell carcinoma: a systematic review of ENT presentations

The aim of this study was to perform a systematic literature review of Merkel cell carcinomas (MCCs) originating exclusively in the ear, nose and throat (ENT) district. An appropriate string was run on PubMed to retrieve articles dealing with ENT presentations of MCC. A double cross-check was performed on citations and full-text articles found using the selected inclusion and exclusion criteria. In total, 43 articles were finally included in the study, describing 51 cases of MCC involving the ENT region: 22/51 (43%) cases involving the ear; 20/51 (39%) cases involving the mucosal sites; 9/51 (18%) cases involving other ENT regions. Patients with mucosal site involvement showed a higher mortality rate from the disease (45%) in comparison with the other two groups, especially when compared with those patients having primary involvement of the ear (22%). The ENT specialist should suspect and consider MCC, especially in elderly patients presenting with a suspicious lesion of the auricular pavilion, so as to avoid misdiagnosis and delayed treatments.