According to the WHO classification of tumors of hematopoietic and lymphoid tissues,
there are three types of plasma cell neoplasms: plasma cell myeloma (PCM), solitary
plasmacytoma of bone and extraosseous plasmacytoma [1]. These tumors are characterized
by proliferation of immature or atypical plasma cells in the bone marrow or tissue
out of the marrow. We report a case of a patient with cutaneous involvement associated
to multiple myeloma (MM), which is rarely seen [2].
A 72-year-old man was admitted to the Department of Dermatology to diagnose firm subcutaneous
nodules of violaceous color located at the trunk, abdomen, limbs and scalp (Figure
1). The patient suffered from numerous internal disorders, including immunoglobulin
G κ multiple myeloma, type 2 diabetes, hypertension, stable angina pectoris, chronic
gastritis, ulcerative colitis, asthma, prostatic hypertrophy and hypercholesterolemia
and took insulin therapy, indapamide, acyclovir, ramipril, amlodipine, doxazosin,
vinpocetine, ciclesonide, ipratropium bromide and salmeterol. The first symptoms of
multiple myeloma occurred 2 years earlier as episodes of anemia and severe pain of
the lumbar spine. Bone marrow biopsy showed 42.4% of plasmocytes and the skull X-ray
revealed disseminated osteolytic lesions. Immunofixation confirmed the presence of
the kappa type IgG monoclonal protein. The patient was treated with cyclophosphamide,
thalidomide and dexamethasone for a year and partial remission was achieved. After
5 months, recurrence of the disease occurred. Treatment with bortezomib, cyclophosphamide
and dexamethasone was initiated and continued for 6 months. One month before the completion
of therapy, skin lesions occurred as described above. The patient was admitted to
the Department of Dermatology. Laboratory examinations showed pancytopenia and an
elevated C-reactive protein level. Abdominal ultrasonography showed gallbladder polyps
and chest X-ray revealed a complete fracture of the sixth left rib. Histopathology
of the nodule demonstrated infiltration of plasmacytoma cells (Figures 2 A, B). Immunohistochemistry
was characteristic of plasmablastic lymphoma with round and extended cells with abundant,
basophilic cytoplasm, eccentrically localized nuclei containing expressed nucleoli,
giant cells and stroma fibrosis. Immunohistochemical characteristics: CD20, CD5, CD10,
CD30 – negative reaction; CD138, CD79α, bcl-2 – positive reaction; Ki67 up to 100%
of cells with positive reaction (Figures 2 C–F). Because of the disease recurrence
with numerous skin nodules, the patient was treated with lenalidomide and dexamethasone
for 3 months, but the treatment had to be stopped due to pancytopenia. No skin lesions
regression was observed during the treatment. The palliative therapy with dexamethasone
was initiated. The patient died soon after with the features of active disease.
Figure 1
Skin lesions – subcutaneous nodules of violaceous color affecting the trunk, abdomen,
limbs and scalp
Figure 2
A, B – Histopathology of the nodule – infiltration of plasmacytoma cells. C–F – Immunohistochemistry
– plasmablasticlymphoma with round and extended cells with abundant, basophilic cytoplasm,
eccentrically localized nuclei containing expressed nucleoli, giant cells and stroma
fibrosis. Immunohistochemical characteristics: CD20, CD5, CD10, CD30 – negative reaction;
CD138 (C), CD79α (D), bcl-2 (E) – positive reaction; Ki67 (F) up to 100% of cells
with positive reaction
Approximately 100 cases of specific cutaneous lesions in patients with MM were described.
The cutaneous tumors may develop as direct extensions of bone lesions or very rarely
independently from bone involvement what we observed in our patient. Skin infiltration
of MM usually is an expression of clinical progress and in some cases is the first
sign of the disease. Clinically, skin lesions usually appear as multiple papules or
cutaneous and subcutaneous nodules in diameter ranging from 1 cm to 5 cm. The nodules
are firm, have smooth surface and red to violaceous color. Skin lesions can affect
any location but most frequently they appear on the trunk and abdomen, next on the
scalp, face, neck, lower extremities and upper extremities [3]. Primary cutaneous
plasmacytoma and secondary plasmacytoma cannot be differentiated in histopathological
examination. Histopathologically, plasma cells infiltrate in nodular or diffuse pattern
involving the dermis and less often also the subcutis [4]. Especially, in secondary
cutaneous pasmacytoma infiltration can occur in interstitial pattern, where plasma
cells are located between the collagen bundles simulating a benign inflammatory infiltrate.
The maturity of plasma cells varies. More often they are atypical, have angulated
and molded borders, pleomorphic nuclei with large nucleoli and granular eosinophilic
cytoplasm. In poorly differentiated lesions plentiful binucleate and multinucleate
plasma cells with mitoses are present [5]. Immunohistochemical studies show monoclonal
plasma cells with strong immunoexpression of CD79A, CD38, and CD138 [4]. The differential
diagnosis includes skin metastases from internal cancers, sarcoidosis, amelanotic
melanoma, T-cell lymphoma, Merkel cell carcinoma, tuberculosis, cryptococcosis and
cutaneous leishmaniasis. However, medical history of a patient should lead as to direction
of plasmacytoma associated with MM. In conclusion, cutaneous involvement in MM is
infrequent. As shows the case of our patient it is a poor prognostic sign, difficult
to treat and patients usually die within 12 months after establishing a diagnosis
[2, 3, 6].
Conflict of interest
The authors declare no conflict of interest.