Merkel cell carcinoma

Merkel cell carcinoma in a patient with B-cell chronic lymphocytic leukemia treated with cladribine and rituximab

Merkel cell carcinoma (MCC) is an uncommon, neuroendocrine skin tumor with an aggressive clinical course. The etiology of the disease is unknown, although sun exposure and immunosuppression may play a role in its development. Coexistence of MCC with chronic lymphocytic leukemia (CLL) is extremely rare and to our knowledge it has been previously described in only 8 patients. We report a 51-year-old woman who presented with a red lump on the right cheek diagnosed as MCC. She had been diagnosed as having CLL 3 years earlier and was treated with 4 courses of cladribine (2-CdA) and subsequently with 4 courses of 2-CdA combined with rituximab. MCC was diagnosed on the basis of histological and immunohistochemical evaluation 2 months after the last course of 2-CdA and rituximab. Surgical excision with tumor-free margins was performed and local adjuvant radiotherapy was applied. Histopathological and immunohistochemical evaluation of the cervical lymph node specimens showed monotonous and diffuse infiltrate of small CD5+, CD20+, CD23+ lymphocytes and no MCC cells were present. To our knowledge, this is the first reported case of MCC occurring in CLL patients soon after treatment with 2-CdA and/or rituximab. The development of MCC in our patient may suggest that this complication rarely observed in CLL patients may have a link with strongly immunosuppressive therapy with 2-CdA and rituximab.

Merkel cells

Merkel cells are post-mitotic cells scattered throughout the epidermis of vertebrates. They are particularly interesting because of the close connections that they develop with sensory nerve endings and the number of peptides they can secrete. These features suggest that they may make an important contribution to skin homeostasis and cutaneous nerve development. However, these cells remain mysterious because they are difficult to study. They have not been successfully cultured and cannot be isolated, severely hampering molecular biology and functional analysis. Merkel cells probably originate in the neural crest of avians and mammalians, and their "spontaneous" appearance in the epidermis may be caused by a neuron-independent epidermal differentiation process. Their functions are still unclear: they take part in mechanoreception or at least interact with neurons, but little is known about their interactions with other epidermal cells. This review provides a new look at these least-known cells of the skin. The numerous peptides they synthesize and release may allow them to communicate with many cells other than neurons, and it is plausible that Merkel cells play a key role in skin physiology and physiopathology.

Biopsia selectiva de ganglio centinela en tumores cutáneos no melanoma

PURPOSE

To assess the feasibility of the Sentinel lymph node biopsy (SLNB) technique in cutaneous non-melanoma malignancies.

MATERIALS AND METHODS

Nine patients were retrospectively evaluated performing a scintigraphy with 99mTc-nanocolloid. On the day of the surgery, an initial dynamic study and static images were obtained. The first drainage station visualized was considered the sentinel node (SLN). The SLN position was marked on the skin and after a correct localization in the surgical field with a gamma probe the SLN was obtained. Patients of this study have been followed up for 8 to 48 months.

RESULTS

Lymphoscintigraphy detected the sentinel node in 88,8 % of our studies (the SLN was not observed in a patient with a Merkel's tumour on the back). The SLN was identified intraoperatively in those patients with positive imaging. Those cases without scintigraphic demonstrated migration were also not found intraoperatively. Histopathological analysis of the SLN showed non metastatic disease and none patient developed metastases or local recurrence in the monitoring period.

CONCLUSIONS

Sentinel node biopsy can be applied to certain cutaneous non-melanoma malignancies. In patients with unclear drainage and to avoid unnecessary lymphadenectomy, the technique offers clear advantages. In our study the SLN analysis was related to the clinical progress. A large number of patients should be examined to truly assess the benefit of this technique in this kind of malignancies and to determinate when the technique must be performed.

Sentinel node biopsy and head and neck tumors—Where do we stand today?

BACKGROUND

Sentinel lymph node sampling may be studied profitably in series of patients with 1 tumor type, such as breast carcinoma, in 1 anatomic locale. The present work analyzes the efficacy of sentinel node sampling in a pathologically diverse group of lesions from an anatomically diverse region such as the head and neck; however, there are risks conflating the findings in different tumors with radically different behaviors, in the process producing muddled data. This report reviews the head and neck experience with sentinel sampling and concludes that certain tumor types that have a known propensity for aggressive behavior are the best candidates for trials employing sentinel node sampling; candidates include many cutaneous melanomas of the head and neck, oropharyngeal squamous carcinomas, and selected thyroid carcinomas. Despite the growing popularity of sentinel node sampling in a variety of regions of the body, however, at this juncture this technique remains an investigational procedure, pending demonstration of a tangible improvement in patient outcome through its use. It is recommended that studies of the efficacy of this technique strive, whenever possible, to segregate results of different tumor types in different head and neck locales from one another so as to produce more focused findings for discrete types of malignancies, and not group together tumor types that may in reality exhibit different biological behaviors.

Tumours of the external ear and temporal bone

Symptoms such as hearing impairment, tinnitus, or a disturbance in sense of balance can generally be attributed to non-neoplastic causes, such as otitis media, otosclerosis, or trauma. Less commonly, auricular signs and symptoms are the result of non-neoplastic and neoplastic space-occupying lesions. The external ear can be the site of development of squamous carcinomas and basal-cell carcinomas; the middle ear and inner ear can host metastatic deposits, and primary squamous carcinomas and adenocarcinomas. Most auricular malignant diseases occur in adulthood; only the rhabdomyosarcomas of the middle ear arise in children. Most malignant diseases of the auricular apparatus are treated by a combination of surgery (commonly including radical excision of temporal bone), radiotherapy, and chemotherapy.

Selective sentinel lymphadenectomy for malignant melanoma, Merkel cell carcinoma, and squamous cell carcinoma

To date, selective sentinel lymphadenectomy (SSL) should be considered a standard approach for staging patients with primary invasive melanoma greater than or equal to 1 mm. It is imperative that the multidisciplinary team master the techniques of preoperative lymphoscintigraphy, intraoperative lymphatic mapping, and postoperative pathologic evaluation of the sentinel lymph nodes (SLNs). An SLN is defined as a blue, "hot" and any subsequent lymph node greater than 10% of the ex vivo count of the hottest lymph node. Any enlarged or indurated lymph node in the nodal basin should be excised. Frozen sections are not recommended. For extremity melanoma, delayed SSL may be performed. Preoperative lymphoscintigraphy for extremity melanoma may be done the night before so that the surgery can be scheduled as the first case of the following day. Every surgeon who uses blue dye should be aware of the potential adverse reaction to isosulfan blue and treatment for such a potential fatal reaction. A complete lymph node dissection is done if the SLN is found to be positive. Elective lymph node dissection (ELND) should not be done if an SSL can be performed as a staging procedure. SSL has further been applied to stage the nodal basin for Merkel cell carcinoma and high-risk squamous cell carcinoma. It is important for investigators involved with the SSL to follow the clinical outcome of these patients, so that the role of SSL can be further defined.