A Spontaneous Regression of an Isolated Lymph Node Metastasis from a Primary Unknown Merkel Cell Carcinoma in a Patient with an Idiopathic Hyper-Eosinophilic Syndrome

Bone marrow metastatic neuroendocrine carcinoma with unknown primary site: A case report and review of the literature

BACKGROUND

Metastatic neuroendocrine carcinoma (NEC) of bone marrow is uncommon. Here, we report a case of bone marrow metastatic NEC with an unknown primary site.

CASE SUMMARY

A 73-year-old Chinese woman was admitted to our hospital because marked chest distress and asthma lasting 1 d on March 18, 2018. She was initially diagnosed with pulmonary infection, cardiac insufficiency, thrombocytopenia and severe anemia. Following treatment with antibiotic therapy, diuresis and blood transfusion, the patient’s symptoms greatly improved. After bone marrow examinations, the patient was diagnosed with bone marrow metastatic NEC, bone marrow necrosis (BMN) and secondary myelofibrosis (MF). Further imaging workup did not show the primary tumor, we presumed that the primary site might regress spontaneously or merely be unexplored due to lack of positron emission tomography with gallium peptide. Everolimus (10 mg/d) was added to the treatment and the best supportive and symptomatic therapies were also administered. Unfortunately, the patient’s condition continued to deteriorate and she died on May 15, 2018.

CONCLUSION

Bone marrow invasion of NEC is rare and our patient who suffered from bone marrow metastatic NEC as well as secondary BMN and MF had an extremely poor prognosis. Bone marrow biopsy plays an important role in the diagnosis of solid tumors invading bone marrow.

Spontaneous Regression of Merkel Cell Carcinoma: Case Report

Merkel cell carcinoma (MCC) is a rare skin neuroendocrine tumor presumably arising from Merkel cells in the basal layer of epidermis. It is an aggressive tumor predominantly found on the head and neck area of elderly people, with a mortality rate around 41% for all stages. Complete spontaneous regression of MCC is seldom observed, mostly in elderly women. We describe complete spontaneous regression of large, histologically confirmed MCC in an elderly woman after biopsy, which occurred incidentally, while waiting for radical surgery with skin flap. Next-generation sequencing with SOPHiA Solid Tumor Plus Solution did not reveal any relevant gene mutations or rearrangements. An update of literature for these very rare cases is provided.